[12] ExtendClientAreaToDecorationsHint behavior of decorations is broken for Windows

Describe the bug

Window Title is shown there, in V11 it was not shown when ExtendClientAreaToDecorationsHint is true.
When Title is shown, it lays above the Menu. Should be hidden.
When Title is set to string.Empty, then in task bar application window has no title.
Menu is not reachable by mouse anymore. Double clicks Expand Unexpand the window.

To Reproduce

  <DockPanel>
	  <DockPanel DockPanel.Dock="Top">
		  <!-- Menu Bar -->
		  <Menu DockPanel.Dock="Left">
			  <MenuItem x:Name="AboutMenuItem"
	              Header="{Binding HeaderInformation}"
			      Foreground="White"
                  Classes="MainMenuHeader">
				  <MenuItem.Icon>
					  <Image Source="../Assets/App.png" />
				  </MenuItem.Icon>
				  <MenuItem.Items>
					  <MenuItem Header="{local:Localize Menu_WebSite}"
								Command="{Binding OpenWebsiteCommand}">
						  <MenuItem.Icon>
							  <Image Source="../Assets/App.png" />
						  </MenuItem.Icon>
					  </MenuItem>
					  <MenuItem Header="{local:Localize Menu_License}" Command="{Binding OpenLicenseCommand}" />
				  </MenuItem.Items>
			  </MenuItem>

I pushed it to https://github.com/drweb86/annotator .

Expected behavior

Support main menu natively on title.

Avalonia version

12.0

OS

Windows

Additional context

No response

https://docs.avaloniaui.net/api/avalonia/input/windowdecorationselementrole

Thanks

<Menu DockPanel.Dock="Left" WindowDecorationProperties.ElementRole="DecorationsElement">

solved issue with mouse click. Now its possible to click menu which is in the bar.

However Window.Title overlaps with menu and its needed for task bar.

Just posted a similar question in Discussions. This does look like a bug since ExtendClientAreaToDecorationsHint="True" also breaks TransparencyLevelHint. Discussions #21170

I've opened #21177, with it the ElementRole on non-decorations won't be necessary anymore for hit testing.

To hide the title bar's text, use the following style:

<Style Selector="WindowDrawnDecorations /template/ Panel#PART_TitleTextPanel > TextBlock">
  <Setter Property="IsVisible" Value="False" />
</Style>

Opened a proposal to more easily configure which parts of the title bar are displayed: #21178

So far migration code look like this. I'll post it for next people having also such windows and trying to migrate.

<Window  ... Title="{local:Localize Window_Title}">
	<Window.Styles>
		**<Style Selector="WindowDrawnDecorations /template/ Panel#PART_TitleTextPanel > TextBlock">
			<Setter Property="IsVisible" Value="{Binding !$parent[Window].ExtendClientAreaToDecorationsHint}" />
		</Style>**
	</Window.Styles>

  <DockPanel>
	  <DockPanel DockPanel.Dock="Top">
		  <!-- Menu Bar -->
		  <Menu DockPanel.Dock="Left" **WindowDecorationProperties.ElementRole="DecorationsElement"**>

@MrJul

Thanks @MrJul

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[12] ExtendClientAreaToDecorationsHint behavior of decorations is broken for Windows #21167

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[12] ExtendClientAreaToDecorationsHint behavior of decorations is broken for Windows #21167

Description

Describe the bug

To Reproduce

Expected behavior

Avalonia version

OS

Additional context

Activity

timunie commented on Apr 12, 2026

drweb86 commented on Apr 12, 2026

anewton commented on Apr 12, 2026

MrJul commented on Apr 13, 2026

MrJul commented on Apr 13, 2026

drweb86 commented on Apr 13, 2026

drweb86 commented on Apr 13, 2026

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