[Tabs] Make initialization logic more robust (#3878)

Author: vnbaaij

examples/Demo/Shared/Pages/Tabs/Examples/TabsDefault.razor

@@ -51,7 +51,7 @@ If checked, the contents of Tab two and three will be loaded after 1 second of p
 @code {
     bool DeferredLoading = false;
 
-    string? activeid = "tab-1";
+    string? activeid = "tab-3";
     FluentTab? changedto;
 
     private void HandleOnTabChange(FluentTab tab)

src/Core/Components/Tabs/FluentTabs.razor.cs

@@ -156,6 +156,11 @@ protected override async Task OnAfterRenderAsync(bool firstRender)
 
             var horizontal = Orientation == Orientation.Horizontal;
             await _jsModuleOverflow.InvokeVoidAsync("fluentOverflowInitialize", _dotNetHelper, Id, horizontal, FLUENT_TAB_TAG, 25);
+
+            if (ActiveTabId is not null)
+            {
+                await HandleOnTabChangedAsync(new TabChangeEventArgs() { ActiveId = ActiveTabId });
+            }
         }
     }