diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index 9086876b7fd..6ea0b8d27ca 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -1,127 +1,127 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.Private.Winforms" Version="6.0.0-alpha.1.20466.4">
+    <Dependency Name="Microsoft.Private.Winforms" Version="6.0.0-alpha.1.20516.2">
       <Uri>https://github.com/dotnet/winforms</Uri>
-      <Sha>6b20c21512a696a383a673e1411793846610000c</Sha>
+      <Sha>da4cd35695fc7fbd19adfc3067f7b44ac90bc9e0</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Dotnet.WinForms.ProjectTemplates" Version="6.0.0-alpha.1.20466.4">
+    <Dependency Name="Microsoft.Dotnet.WinForms.ProjectTemplates" Version="6.0.0-alpha.1.20516.2">
       <Uri>https://github.com/dotnet/winforms</Uri>
-      <Sha>6b20c21512a696a383a673e1411793846610000c</Sha>
+      <Sha>da4cd35695fc7fbd19adfc3067f7b44ac90bc9e0</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Win32.Registry" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="Microsoft.Win32.Registry" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.CodeDom" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.CodeDom" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.Configuration.ConfigurationManager" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Configuration.ConfigurationManager" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.Diagnostics.EventLog" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Diagnostics.EventLog" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.DirectoryServices" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.DirectoryServices" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.Drawing.Common" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Drawing.Common" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
     <Dependency Name="System.Reflection.Emit" Version="5.0.0-alpha.1.19563.6">
       <Uri>https://github.com/dotnet/corefx</Uri>
       <Sha>5cee7c97d602f294e27c582d4dab81ec388f1d7b</Sha>
     </Dependency>
-    <Dependency Name="System.Reflection.MetadataLoadContext" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Reflection.MetadataLoadContext" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.Security.AccessControl" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Security.AccessControl" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.Security.Cryptography.Xml" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Security.Cryptography.Xml" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.Security.Permissions" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Security.Permissions" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.Security.Principal.Windows" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Security.Principal.Windows" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.Windows.Extensions" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Windows.Extensions" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.Platforms" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="Microsoft.NETCore.Platforms" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
     <Dependency Name="Microsoft.DotNet.Wpf.DncEng" Version="6.0.0-alpha.1.20516.2">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-int</Uri>
       <Sha>193292b151b87389f43db4bde1d47a000afa266a</Sha>
     </Dependency>
-    <Dependency Name="System.IO.Packaging" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.IO.Packaging" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
     <Dependency Name="Microsoft.NETCore.Runtime.CoreCLR" Version="5.0.0-alpha1.19562.1">
       <Uri>https://github.com/dotnet/coreclr</Uri>
       <Sha>d5bb8bf2437d447750cf0203dd55bb5160ff36b8</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.ILDAsm" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="Microsoft.NETCore.ILDAsm" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.ILAsm" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="Microsoft.NETCore.ILAsm" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="System.Resources.Extensions" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="System.Resources.Extensions" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.App.Internal" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="Microsoft.NETCore.App.Internal" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.App.Ref" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="Microsoft.NETCore.App.Ref" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.App.Runtime.win-x64" Version="6.0.0-alpha.1.20428.2" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="Microsoft.NETCore.App.Runtime.win-x64" Version="6.0.0-alpha.1.20515.8" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>
-      <Sha>e6b9b48f3466c25e17509137e3931229f406b425</Sha>
+      <Sha>722b8a660e7e0c59419196be102784244883ff08</Sha>
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>
-    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="5.0.0-beta.20464.13">
+    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="6.0.0-beta.20509.12">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>bd918c64b786bdba42e895e4cb93603e5a2ca608</Sha>
+      <Sha>f2f45f7a856fe4949735e574f7a0350bda48264f</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.CodeAnalysis" Version="5.0.0-beta.20464.13">
+    <Dependency Name="Microsoft.DotNet.CodeAnalysis" Version="6.0.0-beta.20509.12">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>bd918c64b786bdba42e895e4cb93603e5a2ca608</Sha>
+      <Sha>f2f45f7a856fe4949735e574f7a0350bda48264f</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Helix.Sdk" Version="5.0.0-beta.20464.13">
+    <Dependency Name="Microsoft.DotNet.Helix.Sdk" Version="6.0.0-beta.20509.12">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>bd918c64b786bdba42e895e4cb93603e5a2ca608</Sha>
+      <Sha>f2f45f7a856fe4949735e574f7a0350bda48264f</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.ApiCompat" Version="5.0.0-beta.20464.13">
+    <Dependency Name="Microsoft.DotNet.ApiCompat" Version="6.0.0-beta.20509.12">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>bd918c64b786bdba42e895e4cb93603e5a2ca608</Sha>
+      <Sha>f2f45f7a856fe4949735e574f7a0350bda48264f</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.GenAPI" Version="5.0.0-beta.20464.13">
+    <Dependency Name="Microsoft.DotNet.GenAPI" Version="6.0.0-beta.20509.12">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>bd918c64b786bdba42e895e4cb93603e5a2ca608</Sha>
+      <Sha>f2f45f7a856fe4949735e574f7a0350bda48264f</Sha>
     </Dependency>
   </ToolsetDependencies>
 </Dependencies>
diff --git a/eng/Versions.props b/eng/Versions.props
index e0165bcb788..9850e7fda49 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -4,48 +4,48 @@
     <VersionPrefix>6.0.0</VersionPrefix>
     <PreReleaseVersionLabel>alpha</PreReleaseVersionLabel>
     <PreReleaseVersionIteration>1</PreReleaseVersionIteration>
-    <SystemIOPackagingVersion>6.0.0-alpha.1.20428.2</SystemIOPackagingVersion>
-    <SystemResourcesExtensionsVersion>6.0.0-alpha.1.20428.2</SystemResourcesExtensionsVersion>
+    <SystemIOPackagingVersion>6.0.0-alpha.1.20515.8</SystemIOPackagingVersion>
+    <SystemResourcesExtensionsVersion>6.0.0-alpha.1.20515.8</SystemResourcesExtensionsVersion>
   </PropertyGroup>
   <!-- NuGet Package Versions -->
   <PropertyGroup>
-    <MicrosoftPrivateWinformsVersion>6.0.0-alpha.1.20466.4</MicrosoftPrivateWinformsVersion>
+    <MicrosoftPrivateWinformsVersion>6.0.0-alpha.1.20516.2</MicrosoftPrivateWinformsVersion>
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/coreclr -->
   <PropertyGroup>
     <MicrosoftNETCoreRuntimeCoreCLRVersion>5.0.0-alpha1.19562.1</MicrosoftNETCoreRuntimeCoreCLRVersion>
-    <MicrosoftNETCoreILDAsmVersion>6.0.0-alpha.1.20428.2</MicrosoftNETCoreILDAsmVersion>
-    <MicrosoftNETCoreILAsmVersion>6.0.0-alpha.1.20428.2</MicrosoftNETCoreILAsmVersion>
+    <MicrosoftNETCoreILDAsmVersion>6.0.0-alpha.1.20515.8</MicrosoftNETCoreILDAsmVersion>
+    <MicrosoftNETCoreILAsmVersion>6.0.0-alpha.1.20515.8</MicrosoftNETCoreILAsmVersion>
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/core-setup -->
   <PropertyGroup>
-    <MicrosoftNETCoreAppInternalVersion>6.0.0-alpha.1.20428.2</MicrosoftNETCoreAppInternalVersion>
-    <MicrosoftNETCoreAppRefVersion>6.0.0-alpha.1.20428.2</MicrosoftNETCoreAppRefVersion>
-    <MicrosoftNETCoreAppRuntimewinx64Version>6.0.0-alpha.1.20428.2</MicrosoftNETCoreAppRuntimewinx64Version>
-    <MicrosoftNETCorePlatformsVersion>6.0.0-alpha.1.20428.2</MicrosoftNETCorePlatformsVersion>
-    <SystemDrawingCommonVersion>6.0.0-alpha.1.20428.2</SystemDrawingCommonVersion>
-    <SystemDirectoryServicesVersion>6.0.0-alpha.1.20428.2</SystemDirectoryServicesVersion>
-    <SystemReflectionMetadataLoadContextVersion>6.0.0-alpha.1.20428.2</SystemReflectionMetadataLoadContextVersion>
+    <MicrosoftNETCoreAppInternalVersion>6.0.0-alpha.1.20515.8</MicrosoftNETCoreAppInternalVersion>
+    <MicrosoftNETCoreAppRefVersion>6.0.0-alpha.1.20515.8</MicrosoftNETCoreAppRefVersion>
+    <MicrosoftNETCoreAppRuntimewinx64Version>6.0.0-alpha.1.20515.8</MicrosoftNETCoreAppRuntimewinx64Version>
+    <MicrosoftNETCorePlatformsVersion>6.0.0-alpha.1.20515.8</MicrosoftNETCorePlatformsVersion>
+    <SystemDrawingCommonVersion>6.0.0-alpha.1.20515.8</SystemDrawingCommonVersion>
+    <SystemDirectoryServicesVersion>6.0.0-alpha.1.20515.8</SystemDirectoryServicesVersion>
+    <SystemReflectionMetadataLoadContextVersion>6.0.0-alpha.1.20515.8</SystemReflectionMetadataLoadContextVersion>
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/corefx via core-setup coherency parent dependency -->
   <PropertyGroup>
-    <MicrosoftWin32RegistryPackageVersion>6.0.0-alpha.1.20428.2</MicrosoftWin32RegistryPackageVersion>
-    <SystemCodeDomPackageVersion>6.0.0-alpha.1.20428.2</SystemCodeDomPackageVersion>
-    <SystemConfigurationConfigurationManagerPackageVersion>6.0.0-alpha.1.20428.2</SystemConfigurationConfigurationManagerPackageVersion>
-    <SystemDiagnosticsEventLogPackageVersion>6.0.0-alpha.1.20428.2</SystemDiagnosticsEventLogPackageVersion>
+    <MicrosoftWin32RegistryPackageVersion>6.0.0-alpha.1.20515.8</MicrosoftWin32RegistryPackageVersion>
+    <SystemCodeDomPackageVersion>6.0.0-alpha.1.20515.8</SystemCodeDomPackageVersion>
+    <SystemConfigurationConfigurationManagerPackageVersion>6.0.0-alpha.1.20515.8</SystemConfigurationConfigurationManagerPackageVersion>
+    <SystemDiagnosticsEventLogPackageVersion>6.0.0-alpha.1.20515.8</SystemDiagnosticsEventLogPackageVersion>
     <SystemReflectionEmitPackageVersion>5.0.0-alpha.1.19563.6</SystemReflectionEmitPackageVersion>
     <SystemReflectionTypeExtensionsPackageVersion>4.6.0-preview4.19176.11</SystemReflectionTypeExtensionsPackageVersion>
-    <SystemSecurityAccessControlPackageVersion>6.0.0-alpha.1.20428.2</SystemSecurityAccessControlPackageVersion>
-    <SystemSecurityCryptographyXmlPackageVersion>6.0.0-alpha.1.20428.2</SystemSecurityCryptographyXmlPackageVersion>
-    <SystemSecurityPermissionsPackageVersion>6.0.0-alpha.1.20428.2</SystemSecurityPermissionsPackageVersion>
-    <SystemSecurityPrincipalWindowsPackageVersion>6.0.0-alpha.1.20428.2</SystemSecurityPrincipalWindowsPackageVersion>
-    <SystemWindowsExtensionsPackageVersion>6.0.0-alpha.1.20428.2</SystemWindowsExtensionsPackageVersion>
+    <SystemSecurityAccessControlPackageVersion>6.0.0-alpha.1.20515.8</SystemSecurityAccessControlPackageVersion>
+    <SystemSecurityCryptographyXmlPackageVersion>6.0.0-alpha.1.20515.8</SystemSecurityCryptographyXmlPackageVersion>
+    <SystemSecurityPermissionsPackageVersion>6.0.0-alpha.1.20515.8</SystemSecurityPermissionsPackageVersion>
+    <SystemSecurityPrincipalWindowsPackageVersion>6.0.0-alpha.1.20515.8</SystemSecurityPrincipalWindowsPackageVersion>
+    <SystemWindowsExtensionsPackageVersion>6.0.0-alpha.1.20515.8</SystemWindowsExtensionsPackageVersion>
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/arcade -->
   <PropertyGroup>
-    <MicrosoftDotNetApiCompatVersion>5.0.0-beta.20464.13</MicrosoftDotNetApiCompatVersion>
-    <MicrosoftDotNetCodeAnalysisPackageVersion>5.0.0-beta.20464.13</MicrosoftDotNetCodeAnalysisPackageVersion>
-    <MicrosoftDotNetGenAPIVersion>5.0.0-beta.20464.13</MicrosoftDotNetGenAPIVersion>
+    <MicrosoftDotNetApiCompatVersion>6.0.0-beta.20509.12</MicrosoftDotNetApiCompatVersion>
+    <MicrosoftDotNetCodeAnalysisPackageVersion>6.0.0-beta.20509.12</MicrosoftDotNetCodeAnalysisPackageVersion>
+    <MicrosoftDotNetGenAPIVersion>6.0.0-beta.20509.12</MicrosoftDotNetGenAPIVersion>
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/corefxlab -->
   <PropertyGroup>
@@ -78,15 +78,6 @@
     <NetFramework48RefAssembliesVersion>0.0.0.1</NetFramework48RefAssembliesVersion>
     <NetFramework472IlToolsVersion>0.0.0.1</NetFramework472IlToolsVersion>
   </PropertyGroup>
-  <PropertyGroup>
-    <RestoreSources>
-      $(RestoreSources);
-      https://dotnet.myget.org/F/dotnet-corefxlab/api/v3/index.json;
-      https://dotnetfeed.blob.core.windows.net/dotnet-windowsdesktop/index.json;
-      https://dotnetfeed.blob.core.windows.net/dotnet-coreclr/index.json;
-      https://dotnetfeed.blob.core.windows.net/dotnet-core/index.json;
-    </RestoreSources>
-  </PropertyGroup>
   <!--Package names-->
   <PropertyGroup>
     <SystemReflectionMetadataLoadContextPackage>System.Reflection.MetadataLoadContext</SystemReflectionMetadataLoadContextPackage>
diff --git a/eng/WpfArcadeSdk/tools/ReferenceAssembly.targets b/eng/WpfArcadeSdk/tools/ReferenceAssembly.targets
index b3256e55bd7..b9fcfbf2ceb 100644
--- a/eng/WpfArcadeSdk/tools/ReferenceAssembly.targets
+++ b/eng/WpfArcadeSdk/tools/ReferenceAssembly.targets
@@ -46,7 +46,7 @@
           Outputs="$(IntellisenseXmlDir)$(AssemblyName).xml">
     <PropertyGroup>
       <!-- Also in global.json -->
-      <DotNetApiDocsNet50>0.0.0.2</DotNetApiDocsNet50>
+      <DotNetApiDocsNet50>0.0.0.3</DotNetApiDocsNet50>
 
       <!-- 
         This blob lives in Azure storage at https://netcorenativeassets.blob.core.windows.net/resource-packages/external/windows/dotnet-api-docs_net5.0/
diff --git a/eng/common/performance/performance-setup.sh b/eng/common/performance/performance-setup.sh
index e0cb8044632..99d1b7bc1fc 100755
--- a/eng/common/performance/performance-setup.sh
+++ b/eng/common/performance/performance-setup.sh
@@ -210,6 +210,7 @@ if [[ "$wasm_runtime_loc" != "" ]]; then
 fi
 
 if [[ "$mono_dotnet" != "" ]] && [[ "$monointerpreter" == "true" ]]; then
+    configurations="$configurations LLVM=$llvm MonoInterpreter=$monointerpreter MonoAOT=$monoaot"
     extra_benchmark_dotnet_arguments="$extra_benchmark_dotnet_arguments --category-exclusion-filter NoInterpreter NoMono"
 fi
 
diff --git a/eng/common/post-build/sourcelink-validation.ps1 b/eng/common/post-build/sourcelink-validation.ps1
index c7e7ae67d81..1728b742b3b 100644
--- a/eng/common/post-build/sourcelink-validation.ps1
+++ b/eng/common/post-build/sourcelink-validation.ps1
@@ -161,9 +161,12 @@ $ValidatePackage = {
 function CheckJobResult(
     $result, 
     $packagePath,
-    [ref]$ValidationFailures) {
-  if ($jobResult.result -ne '0') {
-    Write-PipelineTelemetryError -Category 'SourceLink' -Message "$packagePath has broken SourceLink links."
+    [ref]$ValidationFailures,
+    [switch]$logErrors) {
+  if ($result -ne '0') {
+    if ($logError) {
+      Write-PipelineTelemetryError -Category 'SourceLink' -Message "$packagePath has broken SourceLink links."
+    }
     $ValidationFailures.Value++
   }
 }
@@ -228,16 +231,14 @@ function ValidateSourceLinkLinks {
 
       foreach ($Job in @(Get-Job -State 'Completed')) {
         $jobResult = Wait-Job -Id $Job.Id | Receive-Job
-        CheckJobResult $jobResult.result $jobResult.packagePath ([ref]$ValidationFailures)
+        CheckJobResult $jobResult.result $jobResult.packagePath ([ref]$ValidationFailures) -LogErrors
         Remove-Job -Id $Job.Id
       }
     }
 
   foreach ($Job in @(Get-Job)) {
     $jobResult = Wait-Job -Id $Job.Id | Receive-Job
-    if ($jobResult -ne '0') {
-      $ValidationFailures++
-    }
+    CheckJobResult $jobResult.result $jobResult.packagePath ([ref]$ValidationFailures)
     Remove-Job -Id $Job.Id
   }
   if ($ValidationFailures -gt 0) {
diff --git a/eng/common/templates/job/job.yml b/eng/common/templates/job/job.yml
index e78ed9a1c6e..8b81a7e5143 100644
--- a/eng/common/templates/job/job.yml
+++ b/eng/common/templates/job/job.yml
@@ -204,7 +204,7 @@ jobs:
 
   - ${{ if eq(parameters.enablePublishTestResults, 'true') }}:
     - task: PublishTestResults@2
-      displayName: Publish Test Results
+      displayName: Publish XUnit Test Results
       inputs:
         testResultsFormat: 'xUnit'
         testResultsFiles: '*.xml' 
@@ -213,6 +213,16 @@ jobs:
         mergeTestResults: ${{ parameters.mergeTestResults }}
       continueOnError: true
       condition: always()
+    - task: PublishTestResults@2
+      displayName: Publish TRX Test Results
+      inputs:
+        testResultsFormat: 'VSTest'
+        testResultsFiles: '*.trx' 
+        searchFolder: '$(Build.SourcesDirectory)/artifacts/TestResults/$(_BuildConfig)'
+        testRunTitle: ${{ coalesce(parameters.testRunTitle, parameters.name, '$(System.JobName)') }}-trx
+        mergeTestResults: ${{ parameters.mergeTestResults }}
+      continueOnError: true
+      condition: always()
     
   - ${{ if and(eq(parameters.enablePublishBuildAssets, true), ne(parameters.enablePublishUsingPipelines, 'true'), eq(parameters.runAsPublic, 'false'), ne(variables['System.TeamProject'], 'public'), notin(variables['Build.Reason'], 'PullRequest')) }}:
     - task: CopyFiles@2
diff --git a/eng/common/templates/post-build/post-build.yml b/eng/common/templates/post-build/post-build.yml
index 0854e489615..761fb1a29c3 100644
--- a/eng/common/templates/post-build/post-build.yml
+++ b/eng/common/templates/post-build/post-build.yml
@@ -67,176 +67,180 @@ parameters:
   VSMasterChannelId: 1012
   
 stages:
-- stage: Validate
-  dependsOn: ${{ parameters.validateDependsOn }}
-  displayName: Validate Build Assets
-  variables:
-    - template: common-variables.yml
-  jobs:
-  - template: setup-maestro-vars.yml
-    parameters:
-      BARBuildId: ${{ parameters.BARBuildId }}
-      PromoteToChannelIds: ${{ parameters.PromoteToChannelIds }}
+- ${{ if or(and(le(parameters.publishingInfraVersion, 2), eq(parameters.inline, 'true')), eq( parameters.enableNugetValidation, 'true'), eq(parameters.enableSigningValidation, 'true'), eq(parameters.enableSourceLinkValidation, 'true'), eq(parameters.SDLValidationParameters.enable, 'true')) }}:
+  - stage: Validate
+    dependsOn: ${{ parameters.validateDependsOn }}
+    displayName: Validate Build Assets
+    variables:
+      - template: common-variables.yml
+    jobs:
+    - template: setup-maestro-vars.yml
+      parameters:
+        BARBuildId: ${{ parameters.BARBuildId }}
+        PromoteToChannelIds: ${{ parameters.PromoteToChannelIds }}
+
+    - ${{ if and(le(parameters.publishingInfraVersion, 2), eq(parameters.inline, 'true')) }}:
+      - job:
+        displayName: Post-build Checks
+        dependsOn: setupMaestroVars
+        variables:
+          - name: TargetChannels
+            value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.TargetChannels'] ]
+        pool:
+          vmImage: 'windows-2019'
+        steps:
+          - task: PowerShell@2
+            displayName: Maestro Channels Consistency
+            inputs:
+              filePath: $(Build.SourcesDirectory)/eng/common/post-build/check-channel-consistency.ps1
+              arguments: -PromoteToChannels "$(TargetChannels)"
+                -AvailableChannelIds ${{parameters.NetEngLatestChannelId}},${{parameters.NetEngValidationChannelId}},${{parameters.NetDev5ChannelId}},${{parameters.NetDev6ChannelId}},${{parameters.GeneralTestingChannelId}},${{parameters.NETCoreToolingDevChannelId}},${{parameters.NETCoreToolingReleaseChannelId}},${{parameters.NETInternalToolingChannelId}},${{parameters.NETCoreExperimentalChannelId}},${{parameters.NetEngServicesIntChannelId}},${{parameters.NetEngServicesProdChannelId}},${{parameters.Net5Preview8ChannelId}},${{parameters.Net5RC1ChannelId}},${{parameters.Net5RC2ChannelId}},${{parameters.NetCoreSDK313xxChannelId}},${{parameters.NetCoreSDK313xxInternalChannelId}},${{parameters.NetCoreSDK314xxChannelId}},${{parameters.NetCoreSDK314xxInternalChannelId}},${{parameters.VS166ChannelId}},${{parameters.VS167ChannelId}},${{parameters.VS168ChannelId}},${{parameters.VSMasterChannelId}}
 
-  - ${{ if and(le(parameters.publishingInfraVersion, 2), eq(parameters.inline, 'true')) }}:
     - job:
-      displayName: Post-build Checks
+      displayName: NuGet Validation
       dependsOn: setupMaestroVars
-      variables:
-        - name: TargetChannels
-          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.TargetChannels'] ]
+      condition: eq( ${{ parameters.enableNugetValidation }}, 'true')
       pool:
         vmImage: 'windows-2019'
+      variables:
+        - name: AzDOProjectName
+          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOProjectName'] ]
+        - name: AzDOPipelineId
+          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOPipelineId'] ]
+        - name: AzDOBuildId
+          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOBuildId'] ]
       steps:
+        - task: DownloadBuildArtifacts@0
+          displayName: Download Package Artifacts
+          inputs:
+            buildType: specific
+            buildVersionToDownload: specific
+            project: $(AzDOProjectName)
+            pipeline: $(AzDOPipelineId)
+            buildId: $(AzDOBuildId)
+            artifactName: PackageArtifacts
+
         - task: PowerShell@2
-          displayName: Maestro Channels Consistency
+          displayName: Validate
           inputs:
-            filePath: $(Build.SourcesDirectory)/eng/common/post-build/check-channel-consistency.ps1
-            arguments: -PromoteToChannels "$(TargetChannels)"
-              -AvailableChannelIds ${{parameters.NetEngLatestChannelId}},${{parameters.NetEngValidationChannelId}},${{parameters.NetDev5ChannelId}},${{parameters.NetDev6ChannelId}},${{parameters.GeneralTestingChannelId}},${{parameters.NETCoreToolingDevChannelId}},${{parameters.NETCoreToolingReleaseChannelId}},${{parameters.NETInternalToolingChannelId}},${{parameters.NETCoreExperimentalChannelId}},${{parameters.NetEngServicesIntChannelId}},${{parameters.NetEngServicesProdChannelId}},${{parameters.Net5Preview8ChannelId}},${{parameters.Net5RC1ChannelId}},${{parameters.Net5RC2ChannelId}},${{parameters.NetCoreSDK313xxChannelId}},${{parameters.NetCoreSDK313xxInternalChannelId}},${{parameters.NetCoreSDK314xxChannelId}},${{parameters.NetCoreSDK314xxInternalChannelId}},${{parameters.VS166ChannelId}},${{parameters.VS167ChannelId}},${{parameters.VS168ChannelId}},${{parameters.VSMasterChannelId}}
-
-  - job:
-    displayName: NuGet Validation
-    dependsOn: setupMaestroVars
-    condition: eq( ${{ parameters.enableNugetValidation }}, 'true')
-    pool:
-      vmImage: 'windows-2019'
-    variables:
-      - name: AzDOProjectName
-        value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOProjectName'] ]
-      - name: AzDOPipelineId
-        value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOPipelineId'] ]
-      - name: AzDOBuildId
-        value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOBuildId'] ]
-    steps:
-      - task: DownloadBuildArtifacts@0
-        displayName: Download Package Artifacts
-        inputs:
-          buildType: specific
-          buildVersionToDownload: specific
-          project: $(AzDOProjectName)
-          pipeline: $(AzDOPipelineId)
-          buildId: $(AzDOBuildId)
-          artifactName: PackageArtifacts
-
-      - task: PowerShell@2
-        displayName: Validate
-        inputs:
-          filePath: $(Build.SourcesDirectory)/eng/common/post-build/nuget-validation.ps1
-          arguments: -PackagesPath $(Build.ArtifactStagingDirectory)/PackageArtifacts/ 
-            -ToolDestinationPath $(Agent.BuildDirectory)/Extract/ 
-
-  - job:
-    displayName: Signing Validation
-    dependsOn: setupMaestroVars
-    condition: eq( ${{ parameters.enableSigningValidation }}, 'true')
-    variables:
-      - template: common-variables.yml
-      - name: AzDOProjectName
-        value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOProjectName'] ]
-      - name: AzDOPipelineId
-        value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOPipelineId'] ]
-      - name: AzDOBuildId
-        value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOBuildId'] ]
-    pool:
-      vmImage: 'windows-2019'
-    steps:
-      - ${{ if eq(parameters.useBuildManifest, true) }}:
+            filePath: $(Build.SourcesDirectory)/eng/common/post-build/nuget-validation.ps1
+            arguments: -PackagesPath $(Build.ArtifactStagingDirectory)/PackageArtifacts/ 
+              -ToolDestinationPath $(Agent.BuildDirectory)/Extract/ 
+
+    - job:
+      displayName: Signing Validation
+      dependsOn: setupMaestroVars
+      condition: eq( ${{ parameters.enableSigningValidation }}, 'true')
+      variables:
+        - template: common-variables.yml
+        - name: AzDOProjectName
+          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOProjectName'] ]
+        - name: AzDOPipelineId
+          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOPipelineId'] ]
+        - name: AzDOBuildId
+          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOBuildId'] ]
+      pool:
+        vmImage: 'windows-2019'
+      steps:
+        - ${{ if eq(parameters.useBuildManifest, true) }}:
+          - task: DownloadBuildArtifacts@0
+            displayName: Download build manifest
+            inputs:
+              buildType: specific
+              buildVersionToDownload: specific
+              project: $(AzDOProjectName)
+              pipeline: $(AzDOPipelineId)
+              buildId: $(AzDOBuildId)
+              artifactName: BuildManifests
         - task: DownloadBuildArtifacts@0
-          displayName: Download build manifest
+          displayName: Download Package Artifacts
           inputs:
             buildType: specific
             buildVersionToDownload: specific
             project: $(AzDOProjectName)
             pipeline: $(AzDOPipelineId)
             buildId: $(AzDOBuildId)
-            artifactName: BuildManifests
-      - task: DownloadBuildArtifacts@0
-        displayName: Download Package Artifacts
-        inputs:
-          buildType: specific
-          buildVersionToDownload: specific
-          project: $(AzDOProjectName)
-          pipeline: $(AzDOPipelineId)
-          buildId: $(AzDOBuildId)
-          artifactName: PackageArtifacts
-
-      # This is necessary whenever we want to publish/restore to an AzDO private feed
-      # Since sdk-task.ps1 tries to restore packages we need to do this authentication here
-      # otherwise it'll complain about accessing a private feed.
-      - task: NuGetAuthenticate@0
-        displayName: 'Authenticate to AzDO Feeds'
-
-      - task: PowerShell@2
-        displayName: Enable cross-org publishing
-        inputs:
-          filePath: eng\common\enable-cross-org-publishing.ps1
-          arguments: -token $(dn-bot-dnceng-artifact-feeds-rw)
-
-      # Signing validation will optionally work with the buildmanifest file which is downloaded from
-      # Azure DevOps above.
-      - task: PowerShell@2
-        displayName: Validate
-        inputs:
-          filePath: eng\common\sdk-task.ps1
-          arguments: -task SigningValidation -restore -msbuildEngine vs
-            /p:PackageBasePath='$(Build.ArtifactStagingDirectory)/PackageArtifacts'
-            /p:SignCheckExclusionsFile='$(Build.SourcesDirectory)/eng/SignCheckExclusionsFile.txt'
-            ${{ parameters.signingValidationAdditionalParameters }}
-
-      - template: ../steps/publish-logs.yml
-        parameters:
-          StageLabel: 'Validation'
-          JobLabel: 'Signing'
-
-  - job:
-    displayName: SourceLink Validation
-    dependsOn: setupMaestroVars
-    condition: eq( ${{ parameters.enableSourceLinkValidation }}, 'true')
-    variables:
-      - template: common-variables.yml
-      - name: AzDOProjectName
-        value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOProjectName'] ]
-      - name: AzDOPipelineId
-        value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOPipelineId'] ]
-      - name: AzDOBuildId
-        value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOBuildId'] ]
-    pool:
-      vmImage: 'windows-2019'
-    steps:
-      - task: DownloadBuildArtifacts@0
-        displayName: Download Blob Artifacts
-        inputs:
-          buildType: specific
-          buildVersionToDownload: specific
-          project: $(AzDOProjectName)
-          pipeline: $(AzDOPipelineId)
-          buildId: $(AzDOBuildId)
-          artifactName: BlobArtifacts
-
-      - task: PowerShell@2
-        displayName: Validate
-        inputs:
-          filePath: $(Build.SourcesDirectory)/eng/common/post-build/sourcelink-validation.ps1
-          arguments: -InputPath $(Build.ArtifactStagingDirectory)/BlobArtifacts/ 
-            -ExtractPath $(Agent.BuildDirectory)/Extract/ 
-            -GHRepoName $(Build.Repository.Name) 
-            -GHCommit $(Build.SourceVersion)
-            -SourcelinkCliVersion $(SourceLinkCLIVersion)
-        continueOnError: true
-
-  - template: /eng/common/templates/job/execute-sdl.yml
-    parameters:
-      enable: ${{ parameters.SDLValidationParameters.enable }}
+            artifactName: PackageArtifacts
+
+        # This is necessary whenever we want to publish/restore to an AzDO private feed
+        # Since sdk-task.ps1 tries to restore packages we need to do this authentication here
+        # otherwise it'll complain about accessing a private feed.
+        - task: NuGetAuthenticate@0
+          displayName: 'Authenticate to AzDO Feeds'
+
+        - task: PowerShell@2
+          displayName: Enable cross-org publishing
+          inputs:
+            filePath: eng\common\enable-cross-org-publishing.ps1
+            arguments: -token $(dn-bot-dnceng-artifact-feeds-rw)
+
+        # Signing validation will optionally work with the buildmanifest file which is downloaded from
+        # Azure DevOps above.
+        - task: PowerShell@2
+          displayName: Validate
+          inputs:
+            filePath: eng\common\sdk-task.ps1
+            arguments: -task SigningValidation -restore -msbuildEngine vs
+              /p:PackageBasePath='$(Build.ArtifactStagingDirectory)/PackageArtifacts'
+              /p:SignCheckExclusionsFile='$(Build.SourcesDirectory)/eng/SignCheckExclusionsFile.txt'
+              ${{ parameters.signingValidationAdditionalParameters }}
+
+        - template: ../steps/publish-logs.yml
+          parameters:
+            StageLabel: 'Validation'
+            JobLabel: 'Signing'
+
+    - job:
+      displayName: SourceLink Validation
       dependsOn: setupMaestroVars
-      additionalParameters: ${{ parameters.SDLValidationParameters.params }}
-      continueOnError: ${{ parameters.SDLValidationParameters.continueOnError }}
-      artifactNames: ${{ parameters.SDLValidationParameters.artifactNames }}
-      downloadArtifacts: ${{ parameters.SDLValidationParameters.downloadArtifacts }}
+      condition: eq( ${{ parameters.enableSourceLinkValidation }}, 'true')
+      variables:
+        - template: common-variables.yml
+        - name: AzDOProjectName
+          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOProjectName'] ]
+        - name: AzDOPipelineId
+          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOPipelineId'] ]
+        - name: AzDOBuildId
+          value: $[ dependencies.setupMaestroVars.outputs['setReleaseVars.AzDOBuildId'] ]
+      pool:
+        vmImage: 'windows-2019'
+      steps:
+        - task: DownloadBuildArtifacts@0
+          displayName: Download Blob Artifacts
+          inputs:
+            buildType: specific
+            buildVersionToDownload: specific
+            project: $(AzDOProjectName)
+            pipeline: $(AzDOPipelineId)
+            buildId: $(AzDOBuildId)
+            artifactName: BlobArtifacts
+
+        - task: PowerShell@2
+          displayName: Validate
+          inputs:
+            filePath: $(Build.SourcesDirectory)/eng/common/post-build/sourcelink-validation.ps1
+            arguments: -InputPath $(Build.ArtifactStagingDirectory)/BlobArtifacts/ 
+              -ExtractPath $(Agent.BuildDirectory)/Extract/ 
+              -GHRepoName $(Build.Repository.Name) 
+              -GHCommit $(Build.SourceVersion)
+              -SourcelinkCliVersion $(SourceLinkCLIVersion)
+          continueOnError: true
+
+    - template: /eng/common/templates/job/execute-sdl.yml
+      parameters:
+        enable: ${{ parameters.SDLValidationParameters.enable }}
+        dependsOn: setupMaestroVars
+        additionalParameters: ${{ parameters.SDLValidationParameters.params }}
+        continueOnError: ${{ parameters.SDLValidationParameters.continueOnError }}
+        artifactNames: ${{ parameters.SDLValidationParameters.artifactNames }}
+        downloadArtifacts: ${{ parameters.SDLValidationParameters.downloadArtifacts }}
 
 - ${{ if or(ge(parameters.publishingInfraVersion, 3), eq(parameters.inline, 'false')) }}:
   - stage: publish_using_darc
-    dependsOn: Validate
+    ${{ if or(eq(parameters.enableNugetValidation, 'true'), eq(parameters.enableSigningValidation, 'true'), eq(parameters.enableSourceLinkValidation, 'true'), eq(parameters.SDLValidationParameters.enable, 'true')) }}:
+      dependsOn: Validate
+    ${{ if and(ne(parameters.enableNugetValidation, 'true'), ne(parameters.enableSigningValidation, 'true'), ne(parameters.enableSourceLinkValidation, 'true'), ne(parameters.SDLValidationParameters.enable, 'true')) }}:
+      dependsOn: ${{ parameters.validateDependsOn }}
     displayName: Publish using Darc
     variables:
       - template: common-variables.yml
diff --git a/eng/common/templates/steps/perf-send-to-helix.yml b/eng/common/templates/steps/perf-send-to-helix.yml
index 8427de59cd1..a468e92ce44 100644
--- a/eng/common/templates/steps/perf-send-to-helix.yml
+++ b/eng/common/templates/steps/perf-send-to-helix.yml
@@ -11,7 +11,7 @@ parameters:
   WorkItemDirectory: ''                  # optional -- a payload directory to zip up and send to Helix; requires WorkItemCommand; incompatible with XUnitProjects
   CorrelationPayloadDirectory: ''        # optional -- a directory to zip up and send to Helix as a correlation payload
   IncludeDotNetCli: false                # optional -- true will download a version of the .NET CLI onto the Helix machine as a correlation payload; requires DotNetCliPackageType and DotNetCliVersion
-  DotNetCliPackageType: ''               # optional -- either 'sdk' or 'runtime'; determines whether the sdk or runtime will be sent to Helix; see https://raw.githubusercontent.com/dotnet/core/master/release-notes/releases.json
+  DotNetCliPackageType: ''               # optional -- either 'sdk', 'runtime' or 'aspnetcore-runtime'; determines whether the sdk or runtime will be sent to Helix; see https://raw.githubusercontent.com/dotnet/core/master/release-notes/releases.json
   DotNetCliVersion: ''                   # optional -- version of the CLI to send to Helix; based on this: https://raw.githubusercontent.com/dotnet/core/master/release-notes/releases.json
   EnableXUnitReporter: false             # optional -- true enables XUnit result reporting to Mission Control
   WaitForWorkItemCompletion: true        # optional -- true will make the task wait until work items have been completed and fail the build if work items fail. False is "fire and forget."
diff --git a/eng/common/templates/steps/send-to-helix.yml b/eng/common/templates/steps/send-to-helix.yml
index 5eceb48725d..bb5f1a92938 100644
--- a/eng/common/templates/steps/send-to-helix.yml
+++ b/eng/common/templates/steps/send-to-helix.yml
@@ -18,7 +18,7 @@ parameters:
   XUnitRuntimeTargetFramework: ''        # optional -- framework to use for the xUnit console runner
   XUnitRunnerVersion: ''                 # optional -- version of the xUnit nuget package you wish to use on Helix; required for XUnitProjects
   IncludeDotNetCli: false                # optional -- true will download a version of the .NET CLI onto the Helix machine as a correlation payload; requires DotNetCliPackageType and DotNetCliVersion
-  DotNetCliPackageType: ''               # optional -- either 'sdk' or 'runtime'; determines whether the sdk or runtime will be sent to Helix; see https://raw.githubusercontent.com/dotnet/core/master/release-notes/releases-index.json
+  DotNetCliPackageType: ''               # optional -- either 'sdk', 'runtime' or 'aspnetcore-runtime'; determines whether the sdk or runtime will be sent to Helix; see https://raw.githubusercontent.com/dotnet/core/master/release-notes/releases-index.json
   DotNetCliVersion: ''                   # optional -- version of the CLI to send to Helix; based on this: https://raw.githubusercontent.com/dotnet/core/master/release-notes/releases-index.json
   EnableXUnitReporter: false             # optional -- true enables XUnit result reporting to Mission Control
   WaitForWorkItemCompletion: true        # optional -- true will make the task wait until work items have been completed and fail the build if work items fail. False is "fire and forget."
diff --git a/global.json b/global.json
index 12014da6b43..09f762e9b08 100644
--- a/global.json
+++ b/global.json
@@ -1,6 +1,6 @@
 {
   "tools": {
-    "dotnet": "5.0.100-rc.1.20452.10",
+    "dotnet": "5.0.100-rc.2.20479.15",
     "runtimes": {
       "dotnet": [
         "2.1.7",
@@ -12,16 +12,16 @@
     }
   },
   "msbuild-sdks": {
-    "Microsoft.DotNet.Arcade.Sdk": "5.0.0-beta.20474.4",
-    "Microsoft.DotNet.Helix.Sdk": "5.0.0-beta.20474.4"
+    "Microsoft.DotNet.Arcade.Sdk": "6.0.0-beta.20509.12",
+    "Microsoft.DotNet.Helix.Sdk": "6.0.0-beta.20509.12"
   },
   "sdk": {
-    "version": "5.0.100-rc.1.20452.10"
+    "version": "5.0.100-rc.2.20479.15"
   },
   "native-tools": {
     "strawberry-perl": "5.28.1.1-1",
     "net-framework-48-ref-assemblies": "0.0.0.1",
-    "dotnet-api-docs_net5.0": "0.0.0.2",
+    "dotnet-api-docs_net5.0": "0.0.0.3",
     "net-framework-472-iltools": "0.0.0.1"
   }
 }
diff --git a/src/Microsoft.DotNet.Wpf/src/DirectWriteForwarder/CPP/DWriteWrapper/Common.h b/src/Microsoft.DotNet.Wpf/src/DirectWriteForwarder/CPP/DWriteWrapper/Common.h
index cf918834cf7..4d82bc8c9a7 100644
--- a/src/Microsoft.DotNet.Wpf/src/DirectWriteForwarder/CPP/DWriteWrapper/Common.h
+++ b/src/Microsoft.DotNet.Wpf/src/DirectWriteForwarder/CPP/DWriteWrapper/Common.h
@@ -84,8 +84,8 @@ private ref class Util sealed
 
     /// <summary>
     /// Exceptions known to have security sensitive data are sanitized in this method,
-    /// by creating copy of original exception without sensitive data and re-thrown.
-    /// Or, to put another way - this funciton acts only on a known whitelist of HRESULT/IErrorInfo combinations, throwing for matches.
+    /// by throwing a copy of the original exception without security sensitive data. 
+    /// Or, to put another way - this function acts only on a list of security sensitive HRESULT/IErrorInfo combinations, throwing for matches.
     /// The IErrorInfo is taken into account in a call to GetExceptionForHR(HRESULT), see MSDN for more details.
     /// </summary>
 
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/IO/Packaging/PseudoWebRequest.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/IO/Packaging/PseudoWebRequest.cs
index 016dd4d81cc..62d9e87f5a0 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/IO/Packaging/PseudoWebRequest.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/IO/Packaging/PseudoWebRequest.cs
@@ -46,6 +46,7 @@ internal class PseudoWebRequest : WebRequest
         /// <param name="packageUri">uri of the package</param>
         /// <param name="partUri">uri of the part - may be null</param>
         /// <param name="cacheEntry">cache entry to base this response on</param>
+        #pragma warning disable SYSLIB0014 
         internal PseudoWebRequest(Uri uri, Uri packageUri, Uri partUri, Package cacheEntry)
         {
             Debug.Assert(uri != null, "PackWebRequest uri cannot be null");
@@ -61,6 +62,7 @@ internal PseudoWebRequest(Uri uri, Uri packageUri, Uri partUri, Package cacheEnt
             // set defaults
             SetDefaults();
         }
+        #pragma warning restore SYSLIB0014 
 
         //------------------------------------------------------
         //
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/WpfWebRequestHelper.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/WpfWebRequestHelper.cs
index 48f12444d7c..38b27cfe9bd 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/WpfWebRequestHelper.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/WpfWebRequestHelper.cs
@@ -72,7 +72,9 @@ internal static WebRequest CreateRequest(Uri uri)
             uri = new Uri(uri.GetLeftPart(UriPartial.Path));
         }
 
+        #pragma warning disable SYSLIB0014 
         WebRequest request = WebRequest.Create(uri);
+        #pragma warning restore SYSLIB0014 
 
         // It is not clear whether WebRequest.Create() can ever return null, but v1 code make this check in
         // a couple of places, so it is still done here, just in case.
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/IO/Packaging/PackWebRequest.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/IO/Packaging/PackWebRequest.cs
index e9b532a9dd6..73e49185fc8 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/IO/Packaging/PackWebRequest.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/IO/Packaging/PackWebRequest.cs
@@ -66,6 +66,7 @@ internal PackWebRequest(Uri uri, Uri packageUri, Uri partUri)
         /// <param name="cachedPackageIsThreadSafe">is the cacheEntry thread-safe?</param>
         /// <remarks>This should only be called by PackWebRequestFactory</remarks>
         /// <exception cref="ArgumentException">Will throw an ArgumentException if the given URI is not of the correct scheme</exception>
+        #pragma warning disable SYSLIB0014 
         internal PackWebRequest(Uri uri, Uri packageUri, Uri partUri, Package cacheEntry,
             bool respectCachePolicy, bool cachedPackageIsThreadSafe)
         {
@@ -89,6 +90,7 @@ internal PackWebRequest(Uri uri, Uri packageUri, Uri partUri, Package cacheEntry
                         "PackWebRequest - working from Package Cache");
 #endif
         }
+        #pragma warning restore SYSLIB0014 
 
         //------------------------------------------------------
         //
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/EllipseGeometry.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/EllipseGeometry.cs
index 8d7c077800c..bc5224d6463 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/EllipseGeometry.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/EllipseGeometry.cs
@@ -160,9 +160,6 @@ internal static Rect GetBoundsHelper(Pen pen, Matrix worldMatrix, Point center,
         {
             Rect rect;
 
-            Debug.Assert(worldMatrix != null);
-            Debug.Assert(geometryMatrix != null);
-
             if ( (pen == null || pen.DoesNotContainGaps) &&
                 worldMatrix.IsIdentity && geometryMatrix.IsIdentity)
             {
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/HostVisual.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/HostVisual.cs
index c1b94aab24d..efab923aa3a 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/HostVisual.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/HostVisual.cs
@@ -125,9 +125,16 @@ internal override void FreeContent(DUCE.Channel channel)
 
             using (CompositionEngineLock.Acquire())
             {
-                DisconnectHostedVisual(
-                    channel,
-                    /* removeChannelFromCollection */ true);
+                // if there's a pending disconnect, do it now preemptively;
+                // otherwise do the disconnect the normal way.
+                // This ensures we do the disconnect before calling base,
+                // as required.
+                if (!DoPendingDisconnect(channel))
+                {
+                    DisconnectHostedVisual(
+                        channel,
+                        /* removeChannelFromCollection */ true);
+                }
             }
 
             base.FreeContent(channel);
@@ -252,7 +259,7 @@ private void EnsureHostedVisualConnected(DUCE.Channel channel)
             //
             if (!(channel.IsSynchronous)
                 && _target != null
-                && !_connectedChannels.Contains(channel))
+                && !_connectedChannels.ContainsKey(channel))
             {
                 Debug.Assert(IsOnChannel(channel));
 
@@ -323,7 +330,15 @@ private void EnsureHostedVisualConnected(DUCE.Channel channel)
                                 channel);
                         }
 
-                        _connectedChannels.Add(channel);
+                        // remember what channel we connected to, and which thread
+                        // did the connection, so that we can disconnect on the
+                        // same thread.  Earlier comments imply this is the HostVisual's
+                        // dispatcher thread, which we assert here.  Even if it's not,
+                        // the code downstream should work, or at least not crash
+                        // (even if channelDispatcher is set to null).
+                        Dispatcher channelDispatcher = Dispatcher.FromThread(Thread.CurrentThread);
+                        Debug.Assert(channelDispatcher == this.Dispatcher, "HostVisual connecting on a second thread");
+                        _connectedChannels.Add(channel, channelDispatcher);
 
                         //
                         // Indicate that that content composition root has been
@@ -364,10 +379,11 @@ private void EnsureHostedVisualConnected(DUCE.Channel channel)
         /// </summary>
         private void DisconnectHostedVisualOnAllChannels()
         {
-            foreach (DUCE.Channel channel in _connectedChannels)
+            IDictionaryEnumerator ide = _connectedChannels.GetEnumerator() as IDictionaryEnumerator;
+            while (ide.MoveNext())
             {
                 DisconnectHostedVisual(
-                    channel,
+                    (DUCE.Channel)ide.Key,
                     /* removeChannelFromCollection */ false);
             }
 
@@ -382,23 +398,41 @@ private void DisconnectHostedVisual(
             DUCE.Channel channel,
             bool removeChannelFromCollection)
         {
-            if (_target != null && _connectedChannels.Contains(channel))
+            Dispatcher channelDispatcher;
+            if (_target != null && _connectedChannels.TryGetValue(channel, out channelDispatcher))
             {
-                DUCE.CompositionNode.RemoveChild(
-                    _proxy.GetHandle(channel),
-                    _target._contentRoot.GetHandle(channel),
-                    channel
-                    );
-
-                //
-                // Release the targets handle. If we had duplicated the handle,
-                // then this removes the duplicated handle, otherwise just decrease
-                // the ref count for VisualTarget.
-                //
-
-                _target._contentRoot.ReleaseOnChannel(channel);
-
-                SetFlags(channel, false, VisualProxyFlags.IsContentNodeConnected);
+                // Adding commands to a channel is not thread-safe,
+                // we must do the actual work on the same dispatcher thread
+                // where the connection happened.
+                if (channelDispatcher != null && channelDispatcher.CheckAccess())
+                {
+                    Disconnect(channel,
+                               channelDispatcher,
+                               _proxy.GetHandle(channel),
+                               _target._contentRoot.GetHandle(channel),
+                               _target._contentRoot);
+                }
+                else
+                {
+                    // marshal to the right thread
+                    if (channelDispatcher != null)
+                    {
+                        DispatcherOperation op = channelDispatcher.BeginInvoke(
+                            DispatcherPriority.Normal,
+                            new DispatcherOperationCallback(DoDisconnectHostedVisual),
+                            channel);
+
+                        _disconnectData = new DisconnectData(
+                                                     op: op,
+                                                     channel: channel,
+                                                     dispatcher: channelDispatcher,
+                                                     hostVisual: this,
+                                                     hostHandle: _proxy.GetHandle(channel),
+                                                     targetHandle: _target._contentRoot.GetHandle(channel),
+                                                     contentRoot: _target._contentRoot,
+                                                     next: _disconnectData);
+                    }
+                }
 
                 if (removeChannelFromCollection)
                 {
@@ -407,6 +441,101 @@ private void DisconnectHostedVisual(
             }
         }
 
+        /// <summary>
+        /// Callback to disconnect on the right thread
+        /// </summary>
+        private object DoDisconnectHostedVisual(object arg)
+        {
+            using (CompositionEngineLock.Acquire())
+            {
+                DoPendingDisconnect((DUCE.Channel)arg);
+            }
+
+            return null;
+        }
+
+        /// <summary>
+        /// Perform a pending disconnect for the given channel.
+        /// This method should be called under the CompositionEngineLock,
+        /// on the thread that owns the channel.  It can be called either
+        /// from the dispatcher callback DoDisconnectHostedVisual or
+        /// from FreeContent, whichever happens to occur first.
+        /// </summary>
+        /// <returns>
+        /// True if a matching request was found and processed.  False if not.
+        /// </returns>
+        private bool DoPendingDisconnect(DUCE.Channel channel)
+        {
+            DisconnectData disconnectData = _disconnectData;
+            DisconnectData previous = null;
+
+            // search the list for an entry matching the given channel
+            while (disconnectData != null && (disconnectData.HostVisual != this || disconnectData.Channel != channel))
+            {
+                previous = disconnectData;
+                disconnectData = disconnectData.Next;
+            }
+
+            // if no match found, do nothing
+            if (disconnectData == null)
+            {
+                return false;
+            }
+
+            // remove the matching entry from the list
+            if (previous == null)
+            {
+                _disconnectData = disconnectData.Next;
+            }
+            else
+            {
+                previous.Next = disconnectData.Next;
+            }
+
+            // cancel the dispatcher callback, (if we're already in it,
+            // this call is a no-op)
+            disconnectData.DispatcherOperation.Abort();
+
+            // do the actual disconnect
+            Disconnect(disconnectData.Channel,
+                       disconnectData.ChannelDispatcher,
+                       disconnectData.HostHandle,
+                       disconnectData.TargetHandle,
+                       disconnectData.ContentRoot);
+
+            return true;
+        }
+
+        /// <summary>
+        /// Do the actual work to disconnect the VisualTarget.
+        /// This is called (on the channel's thread) either from
+        /// DisconnectHostedVisual or from DoPendingDisconnect,
+        /// depending on which thread the request arrived on.
+        /// </summary>
+        private void Disconnect(DUCE.Channel channel,
+                                Dispatcher channelDispatcher,
+                                DUCE.ResourceHandle hostHandle,
+                                DUCE.ResourceHandle targetHandle,
+                                DUCE.MultiChannelResource contentRoot)
+        {
+            channelDispatcher.VerifyAccess();
+
+            DUCE.CompositionNode.RemoveChild(
+                hostHandle,
+                targetHandle,
+                channel
+                );
+
+            //
+            // Release the targets handle. If we had duplicated the handle,
+            // then this removes the duplicated handle, otherwise just decrease
+            // the ref count for VisualTarget.
+            //
+
+            contentRoot.ReleaseOnChannel(channel);
+
+            SetFlags(channel, false, VisualProxyFlags.IsContentNodeConnected);
+        }
 
         /// <summary>
         /// Invalidate this visual.
@@ -443,7 +572,49 @@ private void Invalidate()
         /// <remarks>
         /// This field is free-threaded and should be accessed from under a lock.
         /// </remarks>
-        private List<DUCE.Channel> _connectedChannels = new List<DUCE.Channel>();
+        private Dictionary<DUCE.Channel, Dispatcher> _connectedChannels = new Dictionary<DUCE.Channel, Dispatcher>();
+
+        /// <summary>
+        /// Data needed to disconnect the visual target.
+        /// </summary>
+        /// <remarks>
+        /// This field is free-threaded and should be accessed from under a lock.
+        /// It's the head of a singly-linked list of pending disconnect requests,
+        /// each identified by the channel and HostVisual.  In practice, the list
+        /// is either empty or has only one entry.
+        /// </remarks>
+        private static DisconnectData _disconnectData;
+
+        private class DisconnectData
+        {
+            public DispatcherOperation DispatcherOperation { get; private set; }
+            public DUCE.Channel Channel { get; private set; }
+            public Dispatcher ChannelDispatcher { get; private set; }
+            public HostVisual HostVisual { get; private set; }
+            public DUCE.ResourceHandle HostHandle { get; private set; }
+            public DUCE.ResourceHandle TargetHandle { get; private set; }
+            public DUCE.MultiChannelResource ContentRoot { get; private set; }
+            public DisconnectData Next { get; set; }
+
+            public DisconnectData(DispatcherOperation op,
+                                  DUCE.Channel channel,
+                                  Dispatcher dispatcher,
+                                  HostVisual hostVisual,
+                                  DUCE.ResourceHandle hostHandle,
+                                  DUCE.ResourceHandle targetHandle,
+                                  DUCE.MultiChannelResource contentRoot,
+                                  DisconnectData next)
+            {
+                DispatcherOperation = op;
+                Channel = channel;
+                ChannelDispatcher = dispatcher;
+                HostVisual = hostVisual;
+                HostHandle = hostHandle;
+                TargetHandle = targetHandle;
+                ContentRoot = contentRoot;
+                Next = next;
+            }
+        }
 
         #endregion Private Fields
     }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/BitmapSourceSafeMILHandle.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/BitmapSourceSafeMILHandle.cs
index 5a11194f1f4..0f53e6288bb 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/BitmapSourceSafeMILHandle.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/BitmapSourceSafeMILHandle.cs
@@ -71,7 +71,7 @@ private static long ComputeEstimatedSize(IntPtr bitmapObject)
         {
             long estimatedSize = 0;
 
-            if (bitmapObject != null && bitmapObject != IntPtr.Zero)
+            if (bitmapObject != IntPtr.Zero)
             {
                 IntPtr wicBitmap;
 
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/WriteableBitmap.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/WriteableBitmap.cs
index d3ae38311b2..3bc0e4ff449 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/WriteableBitmap.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/WriteableBitmap.cs
@@ -85,15 +85,6 @@ BitmapPalette palette
             // Sanitize inputs
             //
 
-            if (pixelFormat == null)
-            {
-                // Backwards Compat:
-                //
-                // The original code would null-ref, but we choose to raise a
-                // better exception.
-                throw new ArgumentNullException("pixelFormat");
-            }
-
             if (pixelFormat.Palettized && palette == null)
             {
                 throw new InvalidOperationException(SR.Get(SRID.Image_IndexedPixelFormatRequiresPalette));
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/LineGeometry.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/LineGeometry.cs
index daa2c16a7e4..34c864211e5 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/LineGeometry.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/LineGeometry.cs
@@ -107,9 +107,6 @@ internal override Rect GetBoundsInternal(Pen pen, Matrix worldMatrix, double tol
         internal static Rect GetBoundsHelper(Pen pen, Matrix worldMatrix, Point pt1, Point pt2,
                                              Matrix geometryMatrix, double tolerance, ToleranceType type)
         {
-            Debug.Assert(worldMatrix != null);
-            Debug.Assert(geometryMatrix != null);
-
             if (pen == null  &&  worldMatrix.IsIdentity && geometryMatrix.IsIdentity)
             {
                 return new Rect(pt1, pt2);
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/RectangleGeometry.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/RectangleGeometry.cs
index a204c8fa2d2..3abf8d26275 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/RectangleGeometry.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/RectangleGeometry.cs
@@ -190,9 +190,6 @@ internal static Rect GetBoundsHelper(Pen pen, Matrix worldMatrix, Rect rect, dou
         {
             Rect boundingRect;
 
-            Debug.Assert(worldMatrix != null);
-            Debug.Assert(geometryMatrix != null);
-
             if (rect.IsEmpty)
             {
                 boundingRect = Rect.Empty;
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media3D/GeneralTransform3DTo2D.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media3D/GeneralTransform3DTo2D.cs
index 48bb9135b85..3fc14575539 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media3D/GeneralTransform3DTo2D.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media3D/GeneralTransform3DTo2D.cs
@@ -43,15 +43,13 @@ public bool TryTransform(Point3D inPoint, out Point result)
             result = new Point();
             
             // project the point
-            if (_projectionTransform != null)
-            {
                Point3D projectedPoint = _projectionTransform.Transform(inPoint);
-
-                if (_transformBetween2D != null)
-                {
-                    result = _transformBetween2D.Transform(new Point(projectedPoint.X, projectedPoint.Y));
-                    success = true;
-                }
-            }            
+            Point3D projectedPoint = _projectionTransform.Transform(inPoint);
+
+            if (_transformBetween2D != null)
+            {
+                result = _transformBetween2D.Transform(new Point(projectedPoint.X, projectedPoint.Y));
+                success = true;
+            }
 
             return success;
         }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/ref/PresentationCore.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/ref/PresentationCore.cs
index 7a6b09d26f0..787b6ad7e18 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/ref/PresentationCore.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/ref/PresentationCore.cs
@@ -6,6 +6,7 @@ public static void AddPackage(System.Uri uri, System.IO.Packaging.Package packag
         public static System.IO.Packaging.Package GetPackage(System.Uri uri) { throw null; }
         public static void RemovePackage(System.Uri uri) { }
     }
+    #pragma warning disable SYSLIB0014 
     public sealed partial class PackWebRequest : System.Net.WebRequest
     {
         internal PackWebRequest() { }
@@ -25,6 +26,7 @@ internal PackWebRequest() { }
         public override System.IO.Stream GetRequestStream() { throw null; }
         public override System.Net.WebResponse GetResponse() { throw null; }
     }
+    #pragma warning restore SYSLIB0014 
     public sealed partial class PackWebRequestFactory : System.Net.IWebRequestCreate
     {
         public PackWebRequestFactory() { }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/IO/Packaging/indexingfiltermarshaler.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/IO/Packaging/indexingfiltermarshaler.cs
index e8e6b15f34c..aaf0caaa619 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/IO/Packaging/indexingfiltermarshaler.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/IO/Packaging/indexingfiltermarshaler.cs
@@ -215,8 +215,9 @@ internal static IntPtr MarshalPropVariant(Object obj)
 
                 // allocate an unmanaged PROPVARIANT to return
                 pNative = Marshal.AllocCoTaskMem(Marshal.SizeOf(typeof(PROPVARIANT)));
-                // Per MSDN, AllocCoTaskMem never returns null. One can't be too careful, though.
-                Invariant.Assert(pNative != null);
+
+                // Per MSDN, AllocCoTaskMem never returns null: check for IntPtr.Zero instead.
+                Invariant.Assert(pNative != IntPtr.Zero);
 
                 // marshal the managed PROPVARIANT into the unmanaged block and return it
                 Marshal.StructureToPtr(v, pNative, false);
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/Printing/printdlgexmarshaler.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/Printing/printdlgexmarshaler.cs
index 38f464a2a95..d5be8f8c31d 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/Printing/printdlgexmarshaler.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/Printing/printdlgexmarshaler.cs
@@ -628,7 +628,7 @@ IntPtr unmanagedBuffer
                 }
                 catch (Exception)
                 {
-                    if (unmanagedBuffer != null)
+                    if (unmanagedBuffer != IntPtr.Zero)
                     {
                         FreeUnmanagedPrintDlgExStruct(unmanagedBuffer);
                         unmanagedBuffer = IntPtr.Zero;
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/CellParaClient.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/CellParaClient.cs
index 14d44788f8c..4b643148c46 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/CellParaClient.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/CellParaClient.cs
@@ -157,7 +157,7 @@ internal void FormatCellFinite(Size subpageSize, IntPtr breakRecordIn, bool isEm
             int dvrTopSpace;
             PTS.FSPAP fspap;
 
-            if(CellParagraph.StructuralCache.DtrList != null && breakRecordIn != null)
+            if(CellParagraph.StructuralCache.DtrList != null && breakRecordIn != IntPtr.Zero)
             {
                 CellParagraph.InvalidateStructure(TextContainerHelper.GetCPFromElement(CellParagraph.StructuralCache.TextContainer, CellParagraph.Element, ElementEdge.BeforeStart));
             }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/WindowsRuntime/Generated/WinRT/Marshalers.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/WindowsRuntime/Generated/WinRT/Marshalers.cs
index cf159ed3b72..ccbf13294a0 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/WindowsRuntime/Generated/WinRT/Marshalers.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/WindowsRuntime/Generated/WinRT/Marshalers.cs
@@ -127,7 +127,7 @@ public void Dispose()
                         marshaler?.Dispose();
                     }
                 }
-                if (_array != null)
+                if (_array != IntPtr.Zero)
                 {
                     Marshal.FreeCoTaskMem(_array);
                 }
@@ -445,7 +445,7 @@ public void Dispose()
                         Marshaler<T>.DisposeMarshaler(marshaler);
                     }
                 }
-                if (_array != null)
+                if (_array != IntPtr.Zero)
                 {
                     Marshal.FreeCoTaskMem(_array);
                 }
@@ -627,7 +627,7 @@ public void Dispose()
                         DisposeMarshaler(marshaler);
                     }
                 }
-                if (_array != null)
+                if (_array != IntPtr.Zero)
                 {
                     Marshal.FreeCoTaskMem(_array);
                 }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Application.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Application.cs
index 0593bbdb3c4..275a575c0d7 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Application.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Application.cs
@@ -700,7 +700,8 @@ public static StreamResourceInfo GetRemoteStream(Uri uriRemote)
             SiteOfOriginContainer sooContainer = (SiteOfOriginContainer)GetResourcePackage(packageUri);
 
             // the SiteOfOriginContainer is shared across threads;  synchronize access to it
-            lock (_packageLock)
+            // using the same lock object as other uses (PackWebResponse+CachedResponse.GetResponseStream)
+            lock (sooContainer)
             {
                 sooPart = sooContainer.GetPart(partUri) as SiteOfOriginPart;
             }
@@ -2017,8 +2018,9 @@ private static PackagePart GetResourceOrContentPart(Uri uri)
             ResourceContainer resContainer = (ResourceContainer)GetResourcePackage(packageUri);
 
             // the ResourceContainer is shared across threads;  synchronize access to it
+            // using the same lock object as other uses (PackWebResponse+CachedResponse.GetResponseStream)
             PackagePart part = null;
-            lock (_packageLock)
+            lock (resContainer)
             {
                 part = resContainer.GetPart(partUri);
             }
@@ -2417,7 +2419,6 @@ private object RunDispatcher(object ignore)
         static private bool                             _appCreatedInThisAppDomain;
         static private Application                      _appInstance;
         static private Assembly                         _resourceAssembly;
-        static private object                           _packageLock = new Object();
 
         // Keep LoadBamlSyncInfo stack so that the Outer LoadBaml and Inner LoadBaml( ) for the same
         // Uri share the related information.
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/DataGridColumnHeadersPresenterAutomationPeer.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/DataGridColumnHeadersPresenterAutomationPeer.cs
index 90d79ea8788..09c2cd62d86 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/DataGridColumnHeadersPresenterAutomationPeer.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/DataGridColumnHeadersPresenterAutomationPeer.cs
@@ -131,7 +131,7 @@ protected override List<AutomationPeer> GetChildrenCore()
 
                     // protection from indistinguishable items - for example, 2 strings with same value
                     // this scenario does not work in ItemsControl however is not checked for.
-                    if (ItemPeers[dataItem] == null)
+                    if (peer != null && ItemPeers[dataItem] == null)
                     {
                         children.Add(peer);
                         ItemPeers[dataItem] = peer;
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/DateTimeAutomationPeer.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/DateTimeAutomationPeer.cs
index 10d71f9d44b..6ed7fd6a0fc 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/DateTimeAutomationPeer.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/DateTimeAutomationPeer.cs
@@ -30,10 +30,6 @@ public sealed class DateTimeAutomationPeer : AutomationPeer, IGridItemProvider,
         internal DateTimeAutomationPeer(DateTime date, Calendar owningCalendar, CalendarMode buttonMode)
             : base()
         {
-            if (date == null)
-            {
-                throw new ArgumentNullException("date");
-            }
             if (owningCalendar == null)
             {
                 throw new ArgumentNullException("owningCalendar");
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/GroupItemAutomationPeer.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/GroupItemAutomationPeer.cs
index a09f0d8194e..ef36a6c382b 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/GroupItemAutomationPeer.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/GroupItemAutomationPeer.cs
@@ -274,8 +274,8 @@ protected override List<AutomationPeer> GetChildrenCore()
                             // but only if we haven't added a peer for this item during this GetChildrenCore call.
                             bool itemMissingPeerInGlobalStorage = itemsControlAP.ItemPeers[item] == null;
 
-                            if (itemMissingPeerInGlobalStorage
-                                || (peer?.GetParent() == this && addedChildren[item] == null))
+                            if (peer != null && (itemMissingPeerInGlobalStorage
+                                || (peer.GetParent() == this && addedChildren[item] == null)))
                             {
                                 children.Add(peer);
                                 addedChildren[item] = peer;
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/ItemsControlAutomationPeer.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/ItemsControlAutomationPeer.cs
index 890eb4f1a41..df43ac5f2cd 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/ItemsControlAutomationPeer.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Automation/Peers/ItemsControlAutomationPeer.cs
@@ -199,7 +199,7 @@ protected override List<AutomationPeer> GetChildrenCore()
 
                     // protection from indistinguishable items - for example, 2 strings with same value
                     // this scenario does not work in ItemsControl however is not checked for.
-                    if (_dataChildren[dataItem] == null)
+                    if (peer != null && _dataChildren[dataItem] == null)
                     {
                         children.Add(peer);
                         _dataChildren[dataItem] = peer;
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Calendar.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Calendar.cs
index 8b483986745..e7b7e7134c0 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Calendar.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Calendar.cs
@@ -1380,23 +1380,20 @@ private void ProcessEndKey(bool shift)
             {
                 case CalendarMode.Month:
                 {
-                    if (this.DisplayDate != null)
-                    {
-                        DateTime? selectedDate = new DateTime(this.DisplayDateInternal.Year, this.DisplayDateInternal.Month, 1);
-
-                        if (DateTimeHelper.CompareYearMonth(DateTime.MaxValue, selectedDate.Value) > 0)
-                        {
-                            // since DisplayDate is not equal to DateTime.MaxValue we are sure selectedDate is not null
-                            selectedDate = DateTimeHelper.AddMonths(selectedDate.Value, 1).Value;
-                            selectedDate = DateTimeHelper.AddDays(selectedDate.Value, -1).Value;
-                        }
-                        else
-                        {
-                            selectedDate = DateTime.MaxValue;
-                        }
+                    DateTime? selectedDate = new DateTime(this.DisplayDateInternal.Year, this.DisplayDateInternal.Month, 1);
 
-                        ProcessSelection(shift, selectedDate);
+                    if (DateTimeHelper.CompareYearMonth(DateTime.MaxValue, selectedDate.Value) > 0)
+                    {
+                        // since DisplayDate is not equal to DateTime.MaxValue we are sure selectedDate is not null
+                        selectedDate = DateTimeHelper.AddMonths(selectedDate.Value, 1).Value;
+                        selectedDate = DateTimeHelper.AddDays(selectedDate.Value, -1).Value;
                     }
+                    else
+                    {
+                        selectedDate = DateTime.MaxValue;
+                    }
+
+                    ProcessSelection(shift, selectedDate);
 
                     break;
                 }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/CalendarBlackoutDatesCollection.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/CalendarBlackoutDatesCollection.cs
index 7d543ccc2e7..0f6c3b403a9 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/CalendarBlackoutDatesCollection.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/CalendarBlackoutDatesCollection.cs
@@ -349,9 +349,6 @@ private bool IsValidThread()
         /// <returns></returns>
         private CalendarDateRange GetContainingDateRange(DateTime date)
         {
-            if (date == null)
-                return null;
-
             for (int i = 0; i < Count; i++)
             {
                 if (DateTimeHelper.InRange(date, this[i]))
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DataGrid.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DataGrid.cs
index 1122e6593ec..08f5e11b4ab 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DataGrid.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DataGrid.cs
@@ -9,6 +9,7 @@
 using System.Collections.Specialized;
 using System.ComponentModel;
 using System.Diagnostics;
+using System.Runtime.InteropServices;
 using System.Security;
 using System.Text;
 using System.Windows.Automation;
@@ -8336,8 +8337,15 @@ protected virtual void OnExecutedCopy(ExecutedRoutedEventArgs args)
                 dataObject.SetData(format, dataGridStringBuilders[format].ToString(), false /*autoConvert*/);
             }
 
-            Clipboard.CriticalSetDataObject(dataObject, true /* Copy */);
-
+            try
+            {
+                Clipboard.CriticalSetDataObject(dataObject, true /* Copy */);
+            }
+            catch (ExternalException)
+            {
+                // Clipboard failed to set the data object - fail silently.
+                return;
+            }
         }
 
         /// <summary>
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DataGridCell.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DataGridCell.cs
index 6f55d34c8dc..6358bf00e7d 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DataGridCell.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DataGridCell.cs
@@ -278,7 +278,7 @@ internal void NotifyPropertyChanged(DependencyObject d, string propertyName, Dep
                     {
                         column.RefreshCellContent(this, propertyName);
                     }
-                    else if (e != null && e.Property != null)
+                    else if (e.Property != null)
                     {
                         column.RefreshCellContent(this, e.Property.Name);
                     }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/PopupControlService.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/PopupControlService.cs
index be669b0e0a7..7a512f3b557 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/PopupControlService.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/PopupControlService.cs
@@ -546,40 +546,51 @@ private void RaiseToolTipClosingEvent(bool reset)
                     }
                     finally
                     {
-                        if (isOpen)
+                        // Raising an event calls out to app code, which
+                        // could cause a re-entrant call to this method that
+                        // sets _currentToopTip to null.  If that happens,
+                        // there's no need to do the work again.
+                        if (_currentToolTip != null)
                         {
-                            _currentToolTip.IsOpen = false;
-
-                            // Setting IsOpen makes call outs to app code. So it is possible that 
-                            // the _currentToolTip is deleted as a result of an action there. If that 
-                            // were the case we do not need to set off the timer to close the tooltip.
-                            if (_currentToolTip != null)
+                            if (isOpen)
                             {
-                                // Keep references and owner set for the fade out or slide animation
-                                // Owner is released when animation completes
-                                _forceCloseTimer = new DispatcherTimer(DispatcherPriority.Normal);
-                                _forceCloseTimer.Interval = Popup.AnimationDelayTime;
-                                _forceCloseTimer.Tick += new EventHandler(OnForceClose);
-                                _forceCloseTimer.Tag = _currentToolTip;
-                                _forceCloseTimer.Start();
+                                _currentToolTip.IsOpen = false;
+
+                                // Setting IsOpen makes call outs to app code. So it is possible that
+                                // the _currentToolTip is destroyed as a result of an action there. If that
+                                // were the case we do not need to set off the timer to close the tooltip.
+                                if (_currentToolTip != null)
+                                {
+                                    // Keep references and owner set for the fade out or slide animation
+                                    // Owner is released when animation completes
+                                    _forceCloseTimer = new DispatcherTimer(DispatcherPriority.Normal);
+                                    _forceCloseTimer.Interval = Popup.AnimationDelayTime;
+                                    _forceCloseTimer.Tick += new EventHandler(OnForceClose);
+                                    _forceCloseTimer.Tag = _currentToolTip;
+                                    _forceCloseTimer.Start();
+                                }
+
+                                _quickShow = true;
+                                ToolTipTimer = new DispatcherTimer(DispatcherPriority.Normal);
+                                ToolTipTimer.Interval = TimeSpan.FromMilliseconds(ToolTipService.GetBetweenShowDelay(o));
+                                ToolTipTimer.Tick += new EventHandler(OnBetweenShowDelay);
+                                ToolTipTimer.Start();
                             }
+                            else
+                            {
+                                // Release owner now
+                                _currentToolTip.ClearValue(OwnerProperty);
 
-                            _quickShow = true;
-                            ToolTipTimer = new DispatcherTimer(DispatcherPriority.Normal);
-                            ToolTipTimer.Interval = TimeSpan.FromMilliseconds(ToolTipService.GetBetweenShowDelay(o));
-                            ToolTipTimer.Tick += new EventHandler(OnBetweenShowDelay);
-                            ToolTipTimer.Start();
-                        }
-                        else
-                        {
-                            // Release owner now
-                            _currentToolTip.ClearValue(OwnerProperty);
+                                if (_ownToolTip)
+                                    BindingOperations.ClearBinding(_currentToolTip, ToolTip.ContentProperty);
+                            }
 
-                            if (_ownToolTip)
-                                BindingOperations.ClearBinding(_currentToolTip, ToolTip.ContentProperty);
+                            if (_currentToolTip != null)
+                            {
+                                _currentToolTip.FromKeyboard = false;
+                                _currentToolTip = null;
+                            }
                         }
-                        _currentToolTip.FromKeyboard = false;
-                        _currentToolTip = null;
                     }
                 }
             }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/CalendarItem.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/CalendarItem.cs
index f19015c935c..29cc92bba9f 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/CalendarItem.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/CalendarItem.cs
@@ -681,7 +681,6 @@ private void Cell_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
                 CalendarKeyboardHelper.GetMetaKeyState(out ctrl, out shift);
 
                 DateTime selectedDate = (DateTime)b.DataContext;
-                Debug.Assert(selectedDate != null);
 
                 switch (this.Owner.SelectionMode)
                 {
@@ -1303,7 +1302,6 @@ private void SetYearModeMonthButtons()
 
                 if (this.Owner != null)
                 {
-                    Debug.Assert(this.Owner.DisplayDateInternal != null);
                     childButton.HasSelectedDays = (DateTimeHelper.CompareYearMonth(day, this.Owner.DisplayDateInternal) == 0);
 
                     if (DateTimeHelper.CompareYearMonth(day, this.Owner.DisplayDateStartInternal) < 0 || DateTimeHelper.CompareYearMonth(day, this.Owner.DisplayDateEndInternal) > 0)
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/HierarchicalVirtualizationConstraints.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/HierarchicalVirtualizationConstraints.cs
index 31d28ed1001..25bf9dbe67a 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/HierarchicalVirtualizationConstraints.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/HierarchicalVirtualizationConstraints.cs
@@ -21,6 +21,7 @@ public HierarchicalVirtualizationConstraints(VirtualizationCacheLength cacheLeng
             _cacheLength = cacheLength;
             _cacheLengthUnit = cacheLengthUnit;
             _viewport = viewport;
+            _scrollGeneration = 0;  // internal field set separately by caller
         }
 
         #endregion
@@ -131,11 +132,22 @@ public override int GetHashCode()
 
         #endregion
 
+        #region Internal properties
+
+        internal long ScrollGeneration
+        {
+            get { return _scrollGeneration; }
+            set { _scrollGeneration = value; }
+        }
+
+        #endregion
+
         #region Data
 
         VirtualizationCacheLength _cacheLength;
         VirtualizationCacheLengthUnit _cacheLengthUnit;
         Rect _viewport;
+        long _scrollGeneration;
 
         #endregion
     }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/SelectedDatesCollection.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/SelectedDatesCollection.cs
index a5c960137f8..969b696f89a 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/SelectedDatesCollection.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/SelectedDatesCollection.cs
@@ -278,7 +278,7 @@ protected override void SetItem(int index, DateTime item)
                 }
                 else
                 {
-                    if (item != null && DateTime.Compare(this[index], item) != 0 && Calendar.IsValidDateSelection(this._owner, item))
+                    if (DateTime.Compare(this[index], item) != 0 && Calendar.IsValidDateSelection(this._owner, item))
                     {
                         removedItems.Add(this[index]);
                         base.SetItem(index, item);
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/TextBlock.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/TextBlock.cs
index 2bd7d036d5e..282b5e18a4e 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/TextBlock.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/TextBlock.cs
@@ -1504,7 +1504,7 @@ protected sealed override Size ArrangeOverride(Size arrangeSize)
                             {
                                 // Check if paragraph ellipsis are added to this line
                                 bool ellipsis = ParagraphEllipsisShownOnLine(i, lineOffset.Y - contentOffset.Y);
-                                line.Format(dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), lineMetrics.TextLineBreak, _textBlockCache._textRunCache, ellipsis);
+                                Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), lineMetrics.TextLineBreak, _textBlockCache._textRunCache, ellipsis);
 
                                 // Check that lineMetrics length and line length are in sync
                                 // Workaround for (Crash when mouse over a Button with TextBlock). Re-enable this assert when MIL Text issue is fixed.
@@ -1638,7 +1638,7 @@ protected sealed override void OnRender(DrawingContext ctx)
                     {
                         using (line)
                         {
-                            line.Format(dcp, wrappingWidth, GetLineProperties(dcp == 0, showParagraphEllipsis, lineProperties), lineMetrics.TextLineBreak, _textBlockCache._textRunCache, showParagraphEllipsis);
+                            Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(dcp == 0, showParagraphEllipsis, lineProperties), lineMetrics.TextLineBreak, _textBlockCache._textRunCache, showParagraphEllipsis);
 
                             // Workaround for (Crash when mouse over a Button with TextBlock). Re-enable this assert when MIL Text issue is fixed.
                             //if (!showParagraphEllipsis)
@@ -1778,7 +1778,7 @@ protected virtual IInputElement InputHitTestCore(Point point)
                     {
                         // Check if paragraph ellipsis are rendered
                         bool ellipsis = ParagraphEllipsisShownOnLine(i, lineOffset);
-                        line.Format(dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
+                        Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
 
                         // Verify consistency of line formatting
                         // Check that lineMetrics.Length is in sync with line.Length
@@ -1902,7 +1902,7 @@ protected virtual ReadOnlyCollection<Rect> GetRectanglesCore(ContentElement chil
                 {
                     // Check if paragraph ellipsis are rendered
                     bool ellipsis = ParagraphEllipsisShownOnLine(lineIndex, lineOffset);
-                    line.Format(lineStart, wrappingWidth, GetLineProperties(lineIndex == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
+                    Format(line, lineMetrics.Length, lineStart, wrappingWidth, GetLineProperties(lineIndex == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
 
                     // Verify consistency of line formatting
                     // Workaround for (Crash when mouse over a Button with TextBlock). Re-enable this assert when MIL Text issue is fixed.
@@ -2171,16 +2171,17 @@ internal void GetLineDetails(int dcp, int index, double lineVOffset, out int cch
             double wrappingWidth = CalcWrappingWidth(RenderSize.Width);
 
             TextRunCache textRunCache = new TextRunCache();
+            LineMetrics lineMetrics = GetLine(index);
 
             // Retrieve details from the line.
-            using(Line line = CreateLine(lineProperties))
+            using (Line line = CreateLine(lineProperties))
             {
                 // Format line. Set showParagraphEllipsis flag to false
                 TextLineBreak textLineBreak = GetLine(index).TextLineBreak;
                 bool ellipsis = ParagraphEllipsisShownOnLine(index, lineVOffset);
-                line.Format(dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), textLineBreak, textRunCache, ellipsis);
+                Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), textLineBreak, textRunCache, ellipsis);
 
-                MS.Internal.Invariant.Assert(GetLine(index).Length == line.Length, "Line length is out of sync");
+                MS.Internal.Invariant.Assert(lineMetrics.Length == line.Length, "Line length is out of sync");
 
                 cchContent = line.ContentLength;
                 cchEllipses = line.GetEllipsesLength();
@@ -2219,15 +2220,16 @@ internal ITextPointer GetTextPositionFromDistance(int dcp, double distance, doub
             lineVOffset -= contentOffset.Y;
 
             TextRunCache textRunCache = new TextRunCache();
+            LineMetrics lineMetrics = GetLine(index);
             ITextPointer pos;
             using(Line line = CreateLine(lineProperties))
             {
                 MS.Internal.Invariant.Assert(index >= 0 && index < LineCount);
                 TextLineBreak textLineBreak = GetLine(index).TextLineBreak;
                 bool ellipsis = ParagraphEllipsisShownOnLine(index, lineVOffset);
-                line.Format(dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), textLineBreak, textRunCache, ellipsis);
+                Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), textLineBreak, textRunCache, ellipsis);
 
-                MS.Internal.Invariant.Assert(GetLine(index).Length == line.Length, "Line length is out of sync");
+                MS.Internal.Invariant.Assert(lineMetrics.Length == line.Length, "Line length is out of sync");
 
                 CharacterHit charIndex = line.GetTextPositionFromDistance(distance);
                 LogicalDirection logicalDirection;
@@ -2297,7 +2299,7 @@ internal Rect GetRectangleFromTextPosition(ITextPointer orientedPosition)
                     using(Line line = CreateLine(lineProperties))
                     {
                         bool ellipsis = ParagraphEllipsisShownOnLine(i, lineOffset);
-                        line.Format(dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
+                        Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
 
                         // Check consistency of line length
                         MS.Internal.Invariant.Assert(lineMetrics.Length == line.Length, "Line length is out of sync");
@@ -2399,7 +2401,7 @@ internal Geometry GetTightBoundingGeometryFromTextPositions(ITextPointer startPo
                     using (line)
                     {
                         bool ellipsis = ParagraphEllipsisShownOnLine(i, lineOffset);
-                        line.Format(dcpLineStart, wrappingWidth, GetLineProperties(dcpLineStart == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
+                        Format(line, lineMetrics.Length, dcpLineStart, wrappingWidth, GetLineProperties(dcpLineStart == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
 
                         if (Invariant.Strict)
                         {
@@ -2503,7 +2505,7 @@ internal bool IsAtCaretUnitBoundary(ITextPointer position, int dcp, int lineInde
             {
                 // Format line. Set showParagraphEllipsis flag to false since we are not using information about
                 // ellipsis to change line offsets in this case.
-                line.Format(dcp, wrappingWidth, GetLineProperties(lineIndex == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, false);
+                Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(lineIndex == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, false);
 
                 // Check consistency of line formatting
                 MS.Internal.Invariant.Assert(lineMetrics.Length == line.Length, "Line length is out of sync");
@@ -2591,7 +2593,7 @@ internal ITextPointer GetNextCaretUnitPosition(ITextPointer position, LogicalDir
             {
                 // Format line. Set showParagraphEllipsis flag to false since we are not using information about
                 // ellipsis to change line offsets in this case.
-                line.Format(dcp, wrappingWidth, GetLineProperties(lineIndex == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, false);
+                Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(lineIndex == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, false);
 
                 // Check consistency of line formatting
                 MS.Internal.Invariant.Assert(lineMetrics.Length == line.Length, "Line length is out of sync");
@@ -2700,7 +2702,7 @@ internal ITextPointer GetBackspaceCaretUnitPosition(ITextPointer position, int d
             {
                 // Format line. Set showParagraphEllipsis flag to false since we are not using information about
                 // ellipsis to change line offsets in this case.
-                line.Format(dcp, wrappingWidth, GetLineProperties(lineIndex == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, false);
+                Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(lineIndex == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, false);
 
                 // Check consistency of line formatting
                 MS.Internal.Invariant.Assert(lineMetrics.Length == line.Length, "Line length is out of sync");
@@ -3326,6 +3328,108 @@ private double CalcWrappingWidth(double width)
             return width;
         }
 
+        // ------------------------------------------------------------------
+        // Wrapper for line.Format that tries to make the same line-break decisions as Measure
+        // ------------------------------------------------------------------
+        private void Format(Line line, int length, int dcp, double wrappingWidth, TextParagraphProperties paragraphProperties, TextLineBreak textLineBreak, TextRunCache textRunCache, bool ellipsis)
+        {
+            line.Format(dcp, wrappingWidth, paragraphProperties, textLineBreak, textRunCache, ellipsis);
+
+            // line.Format can reflow (make a different line-break
+            // decision than it did during measure), contrary to the comment
+            // in CalcWrappingWidth "Reflowing will not happen when Width is
+            // between _previousDesiredSize.Width and ReferenceWidth", if the
+            // line contains text that gets shaped in a way that reduces the
+            // total width.  Here is an example.
+            //  Text="ABCDE IAATA Corp."  TextWrapping=Wrap  ReferenceWidth=115
+            //  1. Measure calls FormatLine(115), which determines that the full
+            //      text is wider than 115 and breaks it after the second word.
+            //      The resulting desired width is 83.3167 - the length of
+            //      the first line "ABCDE IAATA"
+            //  2. Render, HitTest, et al. call FormatLine(83.3167), which determines
+            //      that the first two words are already wider than 83.3167 and
+            //      breaks after the first word.
+            //  3. FormatLine uses unshaped glyph widths to determine how much text
+            //      to consider in line-breaking decisions.  But it reports the
+            //      width of the lines it produces using shaped glyph widths.
+            //      In the example, the sequence "ATA" gets kerned closer together,
+            //      making the shaped width of the first two words (83.3167)
+            //      about 2.6 pixels less than the unshaped width (85.96).
+            //      This is enough to produce the "reflowing".
+            // The consequences of reflowing are bad.  In the example, the second
+            // word is not rendered, and programmatic editing crashes with FailFast.
+            //
+            // In light of this, we need to work harder to ensure that reflowing
+            // doesn't happen.  The obvious idea to accomplish this is to change
+            // FormatLine to use shaped widths throughout, but that would mean
+            // changing the callbacks from LineServices and DWrite, and asserting
+            // that the changes have no unforseen consequences - out of scope.
+            // Instead, we'll call FormatLine with a target width large enough
+            // to produce the right line-break.
+            //
+            // This has consequences, especially when TextAlignment=Justify -
+            // the line is justified to the larger width rather than to wrappingWidth,
+            // which makes the text extend past the arrange-rect.  To mitigate this,
+            // use the smallest width between wrappingWidth and ReferenceWidth that produces the
+            // right line-break.
+            //
+            // This fixes the cases of missing text and FailFast, at the cost of
+            //      1. more calls to FormatLine (perf hit)
+            //      2. justified text sticks out of the arrange-rect
+            // It's pay-for-play - we only do it on lines that reflow.
+
+            if (line.Length < length)   // reflow happened
+            {
+                double goodWidth = _referenceSize.Width;    // no reflow at this width
+                double badWidth = wrappingWidth;            // reflow at this width
+                // Make sure that TextFormatter limitations are not exceeded.
+                TextDpi.EnsureValidLineWidth(ref goodWidth); // wrappingWidth is already valid, per CalcWrappingWidth
+
+                // The smallest good width can't be calcluated in advance, as it's
+                // dependent on the shaped and unshaped glyph-widths and the available
+                // width in a complicated way.  Instead, binary search.
+                const double tolerance = 0.01;  // allow a small overshoot, to limit the number of iterations
+
+                // In practice, the smallest good width is quite close to wrappingWidth,
+                // so start with "bottom-up binary search".
+                for (double delta = tolerance; /* goodWidth not found */; delta *= 2.0)
+                {
+                    double width = badWidth + delta;
+                    if (width > goodWidth)
+                        break;      // don't increase goodWidth
+
+                    line.Format(dcp, width, paragraphProperties, textLineBreak, textRunCache, ellipsis);
+                    if (line.Length < length)
+                    {
+                        badWidth = width;
+                    }
+                    else
+                    {
+                        goodWidth = width;
+                        break;
+                    }
+                }
+
+                // now do a regular binary search on the remaining interval
+                for (double delta = (goodWidth - badWidth) / 2.0; delta > tolerance; delta /= 2.0)
+                {
+                    double width = badWidth + delta;
+                    line.Format(dcp, width, paragraphProperties, textLineBreak, textRunCache, ellipsis);
+                    if (line.Length < length)
+                    {
+                        badWidth = width;
+                    }
+                    else
+                    {
+                        goodWidth = width;
+                    }
+                }
+
+                // now format at goodwidth, with no reflow
+                line.Format(dcp, goodWidth, paragraphProperties, textLineBreak, textRunCache, ellipsis);
+            }
+        }
+
         // ------------------------------------------------------------------
         // Aborts calculation by throwing exception if world has changed
         // while in measure / arrange / render process.
@@ -3415,7 +3519,7 @@ private void AlignContent()
                 using (line)
                 {
                     bool ellipsis = ParagraphEllipsisShownOnLine(i, lineOffset);
-                    line.Format(dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
+                    Format(line, lineMetrics.Length, dcp, wrappingWidth, GetLineProperties(dcp == 0, lineProperties), lineMetrics.TextLineBreak, textRunCache, ellipsis);
                     double lineHeight = CalcLineAdvance(line.Height, lineProperties);
 
                     // Check consistency of line formatting
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/VirtualizingStackPanel.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/VirtualizingStackPanel.cs
index 269b64e1cf5..d85ce7355cd 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/VirtualizingStackPanel.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/VirtualizingStackPanel.cs
@@ -511,6 +511,8 @@ private void SetHorizontalOffsetImpl(double offset, bool setAnchorInformation)
                     // offset/extent, which ends up scrolling to a "random" place.
                     if (!IsVSP45Compat && Orientation == Orientation.Horizontal)
                     {
+                        IncrementScrollGeneration();
+
                         double delta = Math.Abs(scrollX - oldViewportOffset.X);
                         if (DoubleUtil.LessThanOrClose(delta, ViewportWidth))
                         {
@@ -637,6 +639,8 @@ private void SetVerticalOffsetImpl(double offset, bool setAnchorInformation)
                     // offset/extent, which ends up scrolling to a "random" place.
                     if (!IsVSP45Compat && Orientation == Orientation.Vertical)
                     {
+                        IncrementScrollGeneration();
+
                         double delta = Math.Abs(scrollY - oldViewportOffset.Y);
                         if (DoubleUtil.LessThanOrClose(delta, ViewportHeight))
                         {
@@ -980,9 +984,19 @@ private void OnAnchorOperation(bool isAnchorOperationPending)
 
                     if (DoubleUtil.LessThan(expectedOffset, 0) || DoubleUtil.GreaterThan(expectedOffset, _scrollData._extent.Width - _scrollData._viewport.Width))
                     {
-                        Debug.Assert(DoubleUtil.AreClose(actualOffset, 0) || DoubleUtil.AreClose(actualOffset, _scrollData._extent.Width - _scrollData._viewport.Width), "The actual offset should already be at the beginning or the end.");
-                        _scrollData._computedOffset.X = actualOffset;
-                        _scrollData._offset.X = actualOffset;
+                        // the condition can fail due to estimated sizes in subtrees that contribute
+                        // to FindScrollOffset(_scrollData._firstContainerInViewport) but not to
+                        // _scrollData._extent.  If that happens, remeasure.
+                        if (DoubleUtil.AreClose(actualOffset, 0) || DoubleUtil.AreClose(actualOffset, _scrollData._extent.Width - _scrollData._viewport.Width))
+                        {
+                            _scrollData._computedOffset.X = actualOffset;
+                            _scrollData._offset.X = actualOffset;
+                        }
+                        else
+                        {
+                            remeasure = true;
+                            _scrollData._offset.X = expectedOffset;
+                        }
                     }
                     else
                     {
@@ -999,9 +1013,19 @@ private void OnAnchorOperation(bool isAnchorOperationPending)
 
                     if (DoubleUtil.LessThan(expectedOffset, 0) || DoubleUtil.GreaterThan(expectedOffset, _scrollData._extent.Height - _scrollData._viewport.Height))
                     {
-                        Debug.Assert(DoubleUtil.AreClose(actualOffset, 0) || DoubleUtil.AreClose(actualOffset, _scrollData._extent.Height - _scrollData._viewport.Height), "The actual offset should already be at the beginning or the end.");
-                        _scrollData._computedOffset.Y = actualOffset;
-                        _scrollData._offset.Y = actualOffset;
+                        // the condition can fail due to estimated sizes in subtrees that contribute
+                        // to FindScrollOffset(_scrollData._firstContainerInViewport) but not to
+                        // _scrollData._extent.  If that happens, remeasure.
+                        if (DoubleUtil.AreClose(actualOffset, 0) || DoubleUtil.AreClose(actualOffset, _scrollData._extent.Height - _scrollData._viewport.Height))
+                        {
+                            _scrollData._computedOffset.Y = actualOffset;
+                            _scrollData._offset.Y = actualOffset;
+                        }
+                        else
+                        {
+                            remeasure = true;
+                            _scrollData._offset.Y = expectedOffset;
+                        }
                     }
                     else
                     {
@@ -1027,6 +1051,9 @@ private void OnAnchorOperation(bool isAnchorOperationPending)
                     if (!isVSP45Compat)
                     {
                         CancelPendingAnchoredInvalidateMeasure();
+
+                        // remeasure from the root should use fresh effective offsets
+                        IncrementScrollGeneration();
                     }
 
                     if (!isAnchorOperationPending)
@@ -2149,6 +2176,7 @@ private Size MeasureOverrideImpl(Size constraint,
                     // The viewport constraint used by this panel.
                     //
                     Rect viewport = Rect.Empty, extendedViewport = Rect.Empty;
+                    long scrollGeneration;
 
                     //
                     // Sizes of cache before/after viewport
@@ -2159,7 +2187,7 @@ private Size MeasureOverrideImpl(Size constraint,
                     //
                     // Initialize the viewport for this panel.
                     //
-                    InitializeViewport(parentItem, parentItemStorageProvider, virtualizationInfoProvider, isHorizontal, constraint, ref viewport, ref cacheSize, ref cacheUnit, out extendedViewport);
+                    InitializeViewport(parentItem, parentItemStorageProvider, virtualizationInfoProvider, isHorizontal, constraint, ref viewport, ref cacheSize, ref cacheUnit, out extendedViewport, out scrollGeneration);
 
                     // ===================================================================================
                     // ===================================================================================
@@ -2401,6 +2429,7 @@ private Size MeasureOverrideImpl(Size constraint,
                                                 ref viewport,
                                                 ref cacheSize,
                                                 ref cacheUnit,
+                                                ref scrollGeneration,
                                                 ref foundFirstItemInViewport,
                                                 ref firstItemInViewportOffset,
                                                 ref stackPixelSize,
@@ -2500,6 +2529,7 @@ private Size MeasureOverrideImpl(Size constraint,
                                                             ref viewport,
                                                             ref cacheSize,
                                                             ref cacheUnit,
+                                                            ref scrollGeneration,
                                                             ref foundFirstItemInViewport,
                                                             ref firstItemInViewportOffset,
                                                             ref stackPixelSize,
@@ -2702,6 +2732,7 @@ private Size MeasureOverrideImpl(Size constraint,
                                             ref viewport,
                                             ref cacheSize,
                                             ref cacheUnit,
+                                            ref scrollGeneration,
                                             ref foundFirstItemInViewport,
                                             ref firstItemInViewportOffset,
                                             ref stackPixelSize,
@@ -2789,9 +2820,10 @@ private Size MeasureOverrideImpl(Size constraint,
                                 ref firstItemInViewportOffset,
                                 ref mustDisableVirtualization,
                                 ref hasVirtualizingChildren,
-                                ref hasBringIntoViewContainerBeenMeasured);
+                                ref hasBringIntoViewContainerBeenMeasured,
+                                ref scrollGeneration);
 
-                                if (ItemsChangedDuringMeasure)
+                            if (ItemsChangedDuringMeasure)
                                 {
                                     // if the Items collection changed, our state is now invalid.  Start over.
                                     remeasure = true;
@@ -2837,9 +2869,10 @@ private Size MeasureOverrideImpl(Size constraint,
                                 ref firstItemInViewportOffset,
                                 ref mustDisableVirtualization,
                                 ref hasVirtualizingChildren,
-                                ref hasBringIntoViewContainerBeenMeasured);
+                                ref hasBringIntoViewContainerBeenMeasured,
+                                ref scrollGeneration);
 
-                                if (ItemsChangedDuringMeasure)
+                            if (ItemsChangedDuringMeasure)
                                 {
                                     // if the Items collection changed, our state is now invalid.  Start over.
                                     remeasure = true;
@@ -3043,7 +3076,8 @@ private Size MeasureOverrideImpl(Size constraint,
                                 virtualizationInfoProvider,
                                 isHorizontal,
                                 areContainersUniformlySized,
-                                uniformOrAverageContainerSize);
+                                uniformOrAverageContainerSize,
+                                scrollGeneration);
 
                             // also revise the offset of the first container, for use in Arrange
                             if (firstContainerInViewport != null)
@@ -3084,7 +3118,8 @@ private Size MeasureOverrideImpl(Size constraint,
                                         ref viewport,
                                         firstContainerInViewport,
                                         firstItemInViewportIndex,
-                                        firstItemInViewportOffset);
+                                        firstItemInViewportOffset,
+                                        scrollGeneration);
                             FirstContainerInformationField.SetValue(this, info);
                         }
                     }
@@ -3167,10 +3202,11 @@ private Size MeasureOverrideImpl(Size constraint,
                     {
                         // save information needed by Snapshot
                         DependencyObject offsetHost = virtualizationInfoProvider as DependencyObject;
+                        EffectiveOffsetInformation effectiveOffsetInfo = (offsetHost != null) ? EffectiveOffsetInformationField.GetValue(offsetHost) : null;
                         SnapshotData data = new SnapshotData {
                             UniformOrAverageContainerSize = uniformOrAverageContainerPixelSize,
                             UniformOrAverageContainerPixelSize = uniformOrAverageContainerPixelSize,
-                            EffectiveOffsets = (offsetHost != null) ? EffectiveOffsetInformationField.GetValue(offsetHost) : null
+                            EffectiveOffsets = (effectiveOffsetInfo != null) ? effectiveOffsetInfo.OffsetList : null
                         };
                         SnapshotDataField.SetValue(this, data);
                     }
@@ -3192,6 +3228,12 @@ private Size MeasureOverrideImpl(Size constraint,
 
             if (remeasure)
             {
+                if (!IsVSP45Compat && IsScrolling)
+                {
+                    // remeasure from the root should use fresh effective offsets
+                    IncrementScrollGeneration();
+                }
+
                 //
                 // Make another pass of MeasureOverride if remeasure is true.
                 //
@@ -3460,10 +3502,11 @@ protected override Size ArrangeOverride(Size arrangeSize)
                     {
                         // save information needed by Snapshot
                         DependencyObject offsetHost = virtualizationInfoProvider as DependencyObject;
+                        EffectiveOffsetInformation effectiveOffsetInfo = (offsetHost != null) ? EffectiveOffsetInformationField.GetValue(offsetHost) : null;
                         SnapshotData data = new SnapshotData {
                             UniformOrAverageContainerSize = uniformOrAverageContainerPixelSize,
                             UniformOrAverageContainerPixelSize = uniformOrAverageContainerPixelSize,
-                            EffectiveOffsets = (offsetHost != null) ? EffectiveOffsetInformationField.GetValue(offsetHost) : null
+                            EffectiveOffsets = (effectiveOffsetInfo != null) ? effectiveOffsetInfo.OffsetList : null
                         };
                         SnapshotDataField.SetValue(this, data);
 
@@ -3810,7 +3853,8 @@ private void UpdateExtent(bool areItemChangesLocal)
                                 virtualizationInfoProvider,
                                 isHorizontal,
                                 areContainersUniformlySized,
-                                uniformOrAverageContainerSize);
+                                uniformOrAverageContainerSize,
+                                info.ScrollGeneration);
                     }
                 }
             }
@@ -4231,7 +4275,8 @@ private void InitializeViewport(
             ref Rect viewport,
             ref VirtualizationCacheLength cacheSize,
             ref VirtualizationCacheLengthUnit cacheUnit,
-            out Rect extendedViewport)
+            out Rect extendedViewport,
+            out long scrollGeneration)
         {
             Size extent = new Size();
             bool isVSP45Compat = IsVSP45Compat;
@@ -4251,6 +4296,7 @@ private void InitializeViewport(
                 offsetY = _scrollData._offset.Y;
                 extent = _scrollData._extent;
                 viewportSize = _scrollData._viewport;
+                scrollGeneration = _scrollData._scrollGeneration;
 
                 if (!IsScrollActive || IgnoreMaxDesiredSize)
                 {
@@ -4413,6 +4459,7 @@ private void InitializeViewport(
                 viewport = virtualizationConstraints.Viewport;
                 cacheSize = virtualizationConstraints.CacheLength;
                 cacheUnit = virtualizationConstraints.CacheLengthUnit;
+                scrollGeneration = virtualizationConstraints.ScrollGeneration;
                 MeasureCaches = virtualizationInfoProvider.InBackgroundLayout;
 
                 if (isVSP45Compat)
@@ -4436,34 +4483,46 @@ private void InitializeViewport(
                     // system.
                     //      This replacement stays in effect until the parent panel gives us
                     // an offset from a more recent coordinate change, after which older
-                    // offsets won't appear again.   Or an offset that's not on the
-                    // list at all, which means a new scroll motion has started.
+                    // offsets won't appear again.   Or until a new scroll motion has started,
+                    // as indicated by a scroll generation that exceeds the one in effect
+                    // when the list was created.
                     DependencyObject container = virtualizationInfoProvider as DependencyObject;
-                    List<Double> offsetList = EffectiveOffsetInformationField.GetValue(container);
-                    if (offsetList != null)
+                    EffectiveOffsetInformation effectiveOffsetInfo = EffectiveOffsetInformationField.GetValue(container);
+                    if (effectiveOffsetInfo != null)
                     {
-                        // find the given offset on the list
-                        double offset = isHorizontal ? viewport.X : viewport.Y;
+                        List<double> offsetList = effectiveOffsetInfo.OffsetList;
                         int index = -1;
-                        for (int i=0, n=offsetList.Count; i<n; ++i)
+
+                        // effective offsets only apply when the scroll generation matches
+                        Debug.Assert(effectiveOffsetInfo.ScrollGeneration <= scrollGeneration,
+                            "stored scroll generation exceeds current - this can't happen");
+                        if (effectiveOffsetInfo.ScrollGeneration >= scrollGeneration)
                         {
-                            if (LayoutDoubleUtil.AreClose(offset, offsetList[i]))
+                            // find the given offset on the list
+                            double offset = isHorizontal ? viewport.X : viewport.Y;
+                            for (int i = 0, n = offsetList.Count; i < n; ++i)
                             {
-                                index = i;
-                                break;
+                                if (LayoutDoubleUtil.AreClose(offset, offsetList[i]))
+                                {
+                                    index = i;
+                                    break;
+                                }
                             }
                         }
 
                         if (ScrollTracer.IsEnabled && ScrollTracer.IsTracing(this))
                         {
-                            object[] args = new object[offsetList.Count + 4];
-                            args[0] = viewport.Location;
-                            args[1] = "at";
-                            args[2] = index;
-                            args[3] = "in";
+                            object[] args = new object[offsetList.Count + 7];
+                            args[0] = "gen";
+                            args[1] = effectiveOffsetInfo.ScrollGeneration;
+                            args[2] = virtualizationConstraints.ScrollGeneration;
+                            args[3] = viewport.Location;
+                            args[4] = "at";
+                            args[5] = index;
+                            args[6] = "in";
                             for (int i=0; i<offsetList.Count; ++i)
                             {
-                                args[i+4] = offsetList[i];
+                                args[i+7] = offsetList[i];
                             }
                             ScrollTracer.Trace(this, ScrollTraceOp.UseSubstOffset,
                                 args);
@@ -4496,6 +4555,7 @@ private void InitializeViewport(
             }
             else
             {
+                scrollGeneration = 0;
                 viewport = new Rect(0, 0, constraint.Width, constraint.Height);
 
                 if (isHorizontal)
@@ -5548,7 +5608,8 @@ private double ComputeEffectiveOffset(
             IHierarchicalVirtualizationAndScrollInfo virtualizationInfoProvider,
             bool isHorizontal,
             bool areContainersUniformlySized,
-            double uniformOrAverageContainerSize)
+            double uniformOrAverageContainerSize,
+            long scrollGeneration)
         {
             if (firstContainer == null || IsViewportEmpty(isHorizontal, viewport))
             {
@@ -5571,7 +5632,8 @@ private double ComputeEffectiveOffset(
             // adjust newOffset by the same amount.   This has the effect of
             // giving the child panel the offset it wants the next time this
             // panel measures the child.
-            List<Double> childOffsetList = EffectiveOffsetInformationField.GetValue(firstContainer);
+            EffectiveOffsetInformation effectiveOffsetInformation = EffectiveOffsetInformationField.GetValue(firstContainer);
+            List<Double> childOffsetList = (effectiveOffsetInformation != null) ? effectiveOffsetInformation.OffsetList : null;
             if (childOffsetList != null)
             {
                 int count = childOffsetList.Count;
@@ -5586,32 +5648,51 @@ private double ComputeEffectiveOffset(
                 // multiple calls to measure this panel before the parent
                 // adjusts to the change in our coordinate system, or calls from
                 // a parent who set its own offset using an older offset from here
-                List<Double> offsetList = EffectiveOffsetInformationField.GetValue(container);
-                if (offsetList == null)
+                effectiveOffsetInformation = EffectiveOffsetInformationField.GetValue(container);
+                if (effectiveOffsetInformation == null || effectiveOffsetInformation.ScrollGeneration != scrollGeneration)
                 {
-                    offsetList = new List<Double>(2);
-                    offsetList.Add(oldOffset);
+                    effectiveOffsetInformation = new EffectiveOffsetInformation(scrollGeneration);
+                    effectiveOffsetInformation.OffsetList.Add(oldOffset);
                 }
 
-                offsetList.Add(newOffset);
+                effectiveOffsetInformation.OffsetList.Add(newOffset);
 
                 if (ScrollTracer.IsEnabled && ScrollTracer.IsTracing(this))
                 {
-                    object[] args = new object[offsetList.Count];
-                    for (int i=0; i<offsetList.Count; ++i)
+                    List<double> offsetList = effectiveOffsetInformation.OffsetList;
+                    object[] args = new object[offsetList.Count + 2];
+                    args[0] = scrollGeneration;
+                    args[1] = ":";
+                    for (int i = 0; i < offsetList.Count; ++i)
                     {
-                        args[i] = offsetList[i];
+                        args[i + 2] = offsetList[i];
                     }
                     ScrollTracer.Trace(this, ScrollTraceOp.StoreSubstOffset,
                         args);
                 }
 
-                EffectiveOffsetInformationField.SetValue(container, offsetList);
+                EffectiveOffsetInformationField.SetValue(container, effectiveOffsetInformation);
             }
 
             return newOffset;
         }
 
+        /// <summary>
+        /// To distinguish effective offsets set during one scrolling operation
+        /// from those set in a different, each scrolling operation in the
+        /// virtualizing direction increments the "scroll generation" counter.
+        /// This counter is saved along with the effective offsets (see
+        /// ComputeEffectiveOffsets), and compared with the current counter
+        /// before applying the effective offset (see InitializeViewport).
+        /// </summary>
+        private void IncrementScrollGeneration()
+        {
+            // This will break if the counter ever rolls over the maximum.
+            // If you do 1000 scroll operations per second, that will
+            // happen in about 280 million years.
+            ++_scrollData._scrollGeneration;
+        }
+
 
         /// <summary>
         /// DesiredSize is normally computed by summing up the size of all items we've generated.  Pixel-based virtualization uses a 'full' desired size.
@@ -6559,6 +6640,7 @@ private void SetViewportForChild(
             Rect parentViewport,
             VirtualizationCacheLength parentCacheSize,
             VirtualizationCacheLengthUnit parentCacheUnit,
+            long scrollGeneration,
             Size stackPixelSize,
             Size stackPixelSizeInViewport,
             Size stackPixelSizeInCacheBeforeViewport,
@@ -6671,10 +6753,12 @@ private void SetViewportForChild(
 
             if (virtualizingChild != null)
             {
-                virtualizingChild.Constraints = new HierarchicalVirtualizationConstraints(
+                HierarchicalVirtualizationConstraints constraints = new HierarchicalVirtualizationConstraints(
                     childCacheSize,
                     childCacheUnit,
                     childViewport);
+                constraints.ScrollGeneration = scrollGeneration;
+                virtualizingChild.Constraints = constraints;
                 virtualizingChild.InBackgroundLayout = MeasureCaches;
                 virtualizingChild.MustDisableVirtualization = mustDisableVirtualization;
             }
@@ -7655,6 +7739,20 @@ private void SyncUniformSizeFlags(
                 if (numContainerSizes > 0)
                 {
                     uniformOrAverageContainerPixelSize = sumOfContainerPixelSizes / numContainerSizes;
+
+                    if (UseLayoutRounding)
+                    {
+                        // apply layout rounding to the average size, so that anchored
+                        // scrolls use rounded sizes throughout.  Otherwise they can
+                        // hang because of rounding done in layout that isn't accounted
+                        // for in OnAnchor.
+                        DpiScale dpi = GetDpi();
+                        double dpiScale = isHorizontal ? dpi.DpiScaleX : dpi.DpiScaleY;
+                        uniformOrAverageContainerPixelSize = RoundLayoutValue(
+                                        Math.Max(uniformOrAverageContainerPixelSize, dpiScale), // don't round down to 0
+                                        dpiScale);
+                    }
+
                     if (IsPixelBased)
                     {
                         uniformOrAverageContainerSize = uniformOrAverageContainerPixelSize;
@@ -7938,7 +8036,8 @@ private void MeasureExistingChildBeyondExtendedViewport(
             ref double firstItemInViewportOffset,
             ref bool mustDisableVirtualization,
             ref bool hasVirtualizingChildren,
-            ref bool hasBringIntoViewContainerBeenMeasured)
+            ref bool hasBringIntoViewContainerBeenMeasured,
+            ref long scrollGeneration)
         {
             object item = ((ItemContainerGenerator)generator).ItemFromContainer((UIElement)children[childIndex]);
             Rect viewport = new Rect();
@@ -7978,6 +8077,7 @@ private void MeasureExistingChildBeyondExtendedViewport(
                 ref viewport,
                 ref cacheSize,
                 ref cacheUnit,
+                ref scrollGeneration,
                 ref foundFirstItemInViewport,
                 ref firstItemInViewportOffset,
                 ref stackPixelSize,
@@ -8018,6 +8118,7 @@ private void MeasureChild(
             ref Rect viewport,
             ref VirtualizationCacheLength cacheSize,
             ref VirtualizationCacheLengthUnit cacheUnit,
+            ref long scrollGeneration,
             ref bool foundFirstItemInViewport,
             ref double firstItemInViewportOffset,
             ref Size stackPixelSize,
@@ -8089,6 +8190,7 @@ private void MeasureChild(
                 viewport,
                 cacheSize,
                 cacheUnit,
+                scrollGeneration,
                 stackPixelSize,
                 stackPixelSizeInViewport,
                 stackPixelSizeInCacheBeforeViewport,
@@ -11589,7 +11691,7 @@ private enum BoolField : byte
         private static readonly UncommonField<DispatcherOperation> AnchoredInvalidateMeasureOperationField = new UncommonField<DispatcherOperation>();
         private static readonly UncommonField<DispatcherOperation> ClearIsScrollActiveOperationField = new UncommonField<DispatcherOperation>();
         private static readonly UncommonField<OffsetInformation> OffsetInformationField = new UncommonField<OffsetInformation>();
-        private static readonly UncommonField<List<Double>> EffectiveOffsetInformationField = new UncommonField<List<Double>>();
+        private static readonly UncommonField<EffectiveOffsetInformation> EffectiveOffsetInformationField = new UncommonField<EffectiveOffsetInformation>();
         private static readonly UncommonField<SnapshotData> SnapshotDataField = new UncommonField<SnapshotData>();
 
         #endregion
@@ -11668,6 +11770,9 @@ internal bool IsEmpty
             internal double _firstContainerOffsetFromViewport;
             internal double _expectedDistanceBetweenViewports;
 
+            // scroll generation - for effective offsets
+            internal long _scrollGeneration;
+
             public Vector Offset
             {
                 get
@@ -11780,13 +11885,15 @@ private class FirstContainerInformation
             public DependencyObject FirstContainer;     // first container visible in viewport
             public int              FirstItemIndex;     // index of corresponding item
             public double           FirstItemOffset;    // offset from top of viewport
+            public long             ScrollGeneration;   // current scroll generation
 
-            public FirstContainerInformation(ref Rect viewport, DependencyObject firstContainer, int firstItemIndex, double firstItemOffset)
+            public FirstContainerInformation(ref Rect viewport, DependencyObject firstContainer, int firstItemIndex, double firstItemOffset, long scrollGeneration)
             {
                 Viewport = viewport;
                 FirstContainer = firstContainer;
                 FirstItemIndex = firstItemIndex;
                 FirstItemOffset = firstItemOffset;
+                ScrollGeneration = scrollGeneration;
             }
         }
 
@@ -11833,6 +11940,19 @@ public Double ItemSize
             }
         }
 
+        // Info needed to support Effective Offsets
+        private class EffectiveOffsetInformation
+        {
+            public long ScrollGeneration { get; private set; }
+            public List<double> OffsetList { get; private set; }
+
+            public EffectiveOffsetInformation(long scrollGeneration)
+            {
+                ScrollGeneration = scrollGeneration;
+                OffsetList = new List<double>(2);
+            }
+        }
+
         #endregion Information caches
 
         #region ScrollTracer
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Data/BindingExpression.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Data/BindingExpression.cs
index 2b25d922d5e..7ccbe125d62 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Data/BindingExpression.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Data/BindingExpression.cs
@@ -220,8 +220,6 @@ internal override void OnPropertyInvalidation(DependencyObject d, DependencyProp
         {
             if (d == null)
                 throw new ArgumentNullException("d");
-            if (args == null)
-                throw new ArgumentNullException("args");
 
             DependencyProperty dp = args.Property;
             if (dp == null)
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/FixedSOMPageConstructor.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/FixedSOMPageConstructor.cs
index 7303173a885..a8a7e5a385d 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/FixedSOMPageConstructor.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/FixedSOMPageConstructor.cs
@@ -717,13 +717,15 @@ private bool _IsCombinable(FixedSOMFixedBlock fixedBlock, FixedSOMTextRun textRu
                 //These two overlap vertically. Let's check whether there is a vertical separator in between
                 double left = (fixedBlockRect.Right < textRunRect.Right) ? fixedBlockRect.Right: textRunRect.Right;
                 double right =(fixedBlockRect.Left > textRunRect.Left) ? fixedBlockRect.Left: textRunRect.Left;
-                if (left > right)
+                if (left < right)
                 {
-                    double temp = left;
-                    left = right;
-                    right = temp;
+                    return (!_lines.IsVerticallySeparated(left, textRunRect.Top, right, textRunRect.Bottom));
+                }
+                else
+                {
+                    // they also overlap horizontally, so they should be combined
+                    return true;
                 }
-                return (!_lines.IsVerticallySeparated(left, textRunRect.Top, right, textRunRect.Bottom));
             }
         }
 
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/FixedTextBuilder.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/FixedTextBuilder.cs
index 90f10ed1826..f147725be83 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/FixedTextBuilder.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/FixedTextBuilder.cs
@@ -1033,7 +1033,7 @@ Matrix transform
                                 newPathPrefix,         // otherwise use this path prefix
                                 constructLines,
                                 fixedNodes,
-                                transform * localTransform.Value
+                                localTransform.Value * transform
                                 );
                     }//endofElementIsCanvas
                 }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/FrameworkElement.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/FrameworkElement.cs
index bfd0d63d767..eb6beefb2ec 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/FrameworkElement.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/FrameworkElement.cs
@@ -4589,7 +4589,8 @@ protected sealed override void ArrangeCore(Rect finalRect)
                 // First, get clipped, transformed, unrounded size.
                 if (useLayoutRounding)
                 {
-                    if (ltd != null && ltd.TransformedUnroundedDS != null)
+                    // 'transformUnroundedDS' is a non-nullable value type and can never be null.
+                    if (ltd != null)
                     {
                         transformedUnroundedDS = ltd.TransformedUnroundedDS;
                         transformedUnroundedDS.Width = Math.Max(0, transformedUnroundedDS.Width - marginWidth);
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Interop/HwndHost.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Interop/HwndHost.cs
index 025b6c68040..f9dba71f6a8 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Interop/HwndHost.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Interop/HwndHost.cs
@@ -983,7 +983,6 @@ private void BuildOrReparentWindow()
                     // window later when a new parent is available
                     var hwnd = SystemResources.GetDpiAwarenessCompatibleNotificationWindow(_hwnd);
                     Debug.Assert(hwnd != null);
-                    Trace.WriteLineIf(hwnd == null, $"- Warning - Notification Window is null\n{new System.Diagnostics.StackTrace(true).ToString()}");
                     if (hwnd != null)
                     {
                         UnsafeNativeMethods.SetParent(_hwnd, new HandleRef(null, hwnd.Handle));
@@ -998,6 +997,10 @@ private void BuildOrReparentWindow()
                         // shutdown event after this HwndHost.
                         SystemResources.DelayHwndShutdown();
                     }
+                    else
+                    {
+                        Trace.WriteLineIf(hwnd == null, $"- Warning - Notification Window is null\n{new System.Diagnostics.StackTrace(true).ToString()}");
+                    }
                 }
             }
             finally
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Standard/NativeMethods.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Standard/NativeMethods.cs
index fc19dd6d92e..1b65ea82a86 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Standard/NativeMethods.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Standard/NativeMethods.cs
@@ -2797,7 +2797,7 @@ public static MONITORINFO GetMonitorInfo(IntPtr hMonitor)
         public static IntPtr GetStockObject(StockObject fnObject)
         {
             IntPtr retPtr = _GetStockObject(fnObject);
-            if (retPtr == null)
+            if (retPtr == IntPtr.Zero)
             {
                 HRESULT.ThrowLastError();
             }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/VisualStateManager.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/VisualStateManager.cs
index 6cfe7cd829b..7824e9107d7 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/VisualStateManager.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/VisualStateManager.cs
@@ -408,7 +408,7 @@ private static Storyboard GenerateDynamicTransitionAnimations(FrameworkElement r
             
             if (transition != null)
             {
-                if (transition.GeneratedDuration != null)
+                if (transition.GeneratedDuration != DurationZero)
                 {
                     dynamic.Duration = transition.GeneratedDuration;
                 }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Window.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Window.cs
index b5537ef5d49..d15232b2f15 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Window.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Window.cs
@@ -6148,7 +6148,7 @@ private static object CoerceRenderTransform(DependencyObject d, object value)
             Transform renderTransformValue = (Transform)value;
 
             if ((value == null) ||
-                (renderTransformValue != null && renderTransformValue.Value != null && renderTransformValue.Value.IsIdentity == true))
+                (renderTransformValue != null && renderTransformValue.Value.IsIdentity == true))
             {
                 // setting this value is allowed.
             }
diff --git a/src/Microsoft.DotNet.Wpf/src/ReachFramework/PrintConfig/FallbackPTProvider.cs b/src/Microsoft.DotNet.Wpf/src/ReachFramework/PrintConfig/FallbackPTProvider.cs
index 2e4eefb9bd4..8d779b5a22f 100644
--- a/src/Microsoft.DotNet.Wpf/src/ReachFramework/PrintConfig/FallbackPTProvider.cs
+++ b/src/Microsoft.DotNet.Wpf/src/ReachFramework/PrintConfig/FallbackPTProvider.cs
@@ -400,7 +400,9 @@ private string OemDriverNamespace
                             CultureInfo.InvariantCulture,
                             DeviceNamespaceFormat,
                             BuildInfo.WCP_VERSION_SUFFIX,
+                            #pragma warning disable SYSLIB0013
                             Uri.EscapeUriString(this._driverName),
+                            #pragma warning restore SYSLIB0013
                             this._driverVersion);
                     }
 
diff --git a/src/Microsoft.DotNet.Wpf/src/Shared/MS/Win32/HwndSubclass.cs b/src/Microsoft.DotNet.Wpf/src/Shared/MS/Win32/HwndSubclass.cs
index e9dc2e01ecc..3048eafdfa3 100644
--- a/src/Microsoft.DotNet.Wpf/src/Shared/MS/Win32/HwndSubclass.cs
+++ b/src/Microsoft.DotNet.Wpf/src/Shared/MS/Win32/HwndSubclass.cs
@@ -553,7 +553,8 @@ private bool UnhookWindowProc(bool force)
 
             //AvDebug.Assert(_gcHandle.IsAllocated, "External GC handle has not been allocated.");
 
-            if(null != _gcHandle)
+            // GCHandle is a non-nullable type.  Check GCHandle.IsAllocated before calling Free().
+            if(_gcHandle.IsAllocated)
                 _gcHandle.Free();
 
             return true;
diff --git a/src/Microsoft.DotNet.Wpf/src/System.Windows.Controls.Ribbon/Microsoft/Windows/Controls/Ribbon/RibbonHelper.cs b/src/Microsoft.DotNet.Wpf/src/System.Windows.Controls.Ribbon/Microsoft/Windows/Controls/Ribbon/RibbonHelper.cs
index dc4658edddb..a8b2f11317b 100644
--- a/src/Microsoft.DotNet.Wpf/src/System.Windows.Controls.Ribbon/Microsoft/Windows/Controls/Ribbon/RibbonHelper.cs
+++ b/src/Microsoft.DotNet.Wpf/src/System.Windows.Controls.Ribbon/Microsoft/Windows/Controls/Ribbon/RibbonHelper.cs
@@ -2326,8 +2326,7 @@ private static void TransferMarkupProperties(object original, object clone)
                             markupProp.PropertyDescriptor.ComponentType == typeof(ItemsControl))
                         {
                             // Skip the ItemsControl.Items property
-                            // since this will be copied as part of
-                            // the whitelist properties.
+                            // since this will be copied automatically.
 
                             continue;
                         }
diff --git a/src/Microsoft.DotNet.Wpf/src/WindowsBase/MS/Internal/Security/RightsManagement/IssuanceLicense.cs b/src/Microsoft.DotNet.Wpf/src/WindowsBase/MS/Internal/Security/RightsManagement/IssuanceLicense.cs
index a7b7ab94970..79e579cbec8 100644
--- a/src/Microsoft.DotNet.Wpf/src/WindowsBase/MS/Internal/Security/RightsManagement/IssuanceLicense.cs
+++ b/src/Microsoft.DotNet.Wpf/src/WindowsBase/MS/Internal/Security/RightsManagement/IssuanceLicense.cs
@@ -180,8 +180,8 @@ private void Initialize(
                 }
             }
 
-            // set metafata as required 
-            if (contentId != null)
+            // set metadata as required 
+            if (contentId != Guid.Empty)
             {
                 hr = SafeNativeMethods.DRMSetMetaData(
                     _issuanceLicenseHandle,
diff --git a/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/SplashScreen.cs b/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/SplashScreen.cs
index 0b895b3dee9..abbf7e8fa01 100644
--- a/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/SplashScreen.cs
+++ b/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/SplashScreen.cs
@@ -238,7 +238,7 @@ private object CloseInternal(Object fadeOutArg)
             // In the case where the developer has specified AutoClose=True and then calls
             // Close(non_zero_timespan) before the auto close operation is dispatched we begin
             // the fadeout immidiately and ignore the later call to close.
-            if (_dt != null || _hwnd == null)
+            if (_dt != null || _hwnd == IntPtr.Zero)
             {
                 return BooleanBoxes.TrueBox;
             }
diff --git a/src/Microsoft.DotNet.Wpf/src/WpfGfx/core/resources/glyphrunslave.cpp b/src/Microsoft.DotNet.Wpf/src/WpfGfx/core/resources/glyphrunslave.cpp
index 9edc9eaf4c6..7c81f299d53 100644
--- a/src/Microsoft.DotNet.Wpf/src/WpfGfx/core/resources/glyphrunslave.cpp
+++ b/src/Microsoft.DotNet.Wpf/src/WpfGfx/core/resources/glyphrunslave.cpp
@@ -1029,14 +1029,6 @@ CGlyphRunResource::GetDWriteRenderingMode(__in IDWriteFontFace *pIDWriteFontFace
                             *pDWriteRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL;
                         }
                     }
-                    else
-                    {
-                        // This assert is here for an equivalence check with .NET Framework 
-                        // when allowing DWrite to choose our rendering mode directly.
-                        Assert((textRenderingMode == MilTextRenderingMode::Auto)
-                            || ((textRenderingMode == MilTextRenderingMode::Aliased)
-                                && !IsDisplayMeasured()));
-                    }
                 }
             }
         }
diff --git a/src/Microsoft.DotNet.Wpf/src/WpfGfx/include/exports.cs b/src/Microsoft.DotNet.Wpf/src/WpfGfx/include/exports.cs
index 5f67d5575a4..ebeae5054ab 100644
--- a/src/Microsoft.DotNet.Wpf/src/WpfGfx/include/exports.cs
+++ b/src/Microsoft.DotNet.Wpf/src/WpfGfx/include/exports.cs
@@ -365,6 +365,15 @@ internal struct ChannelSet
         /// channel.
         /// </summary>
         internal sealed partial class Channel
+        #if ENFORCE_CHANNEL_THREAD_ACCESS
+            : System.Windows.Threading.DispatcherObject
+            // "Producer" operations - adding commands et al. - should only be done
+            // on the thread that created the channel.  These operations are on the
+            // hot path, so we don't add the cost of enforcement.  To detect
+            // violations (which can lead to render-thread failures that
+            // are very difficult to diagnose), build
+            // PresentationCore with ENFORCE_CHANNEL_THREAD_ACCESS defined.
+        #endif
         {
             /// <summary>
             /// Primary channel.
@@ -768,6 +777,10 @@ unsafe internal void SendCommand(
                 int cSize,
                 bool sendInSeparateBatch)
             {
+                #if ENFORCE_CHANNEL_THREAD_ACCESS
+                VerifyAccess();
+                #endif
+
                 checked
                 {
                     Invariant.Assert(pCommandData != (byte*)0 && cSize > 0);
@@ -808,6 +821,10 @@ unsafe internal void BeginCommand(
                 int cbSize,
                 int cbExtra)
             {
+                #if ENFORCE_CHANNEL_THREAD_ACCESS
+                VerifyAccess();
+                #endif
+
                 checked
                 {
                     Invariant.Assert(cbSize > 0);