More changes for non-toplevel visual tree roots. (#20732)

* Make some overlay-related types/members internal

* Make sure that TopLevel is no longer the actual root of the visual tree. This is needed for our future changes.

* API diff

* Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Fixed incorrect test

* Make automation to target FocusRoot

* api diff

* Hide WindowBase/EmbeddableControlRoot's parents from automation

* api diff

* Separate automation root and visual root for automation purposes

* Hide ChromeOverlayLayer from public API

* Synchronize WindowBase visibility to VisualRoot

* Hide WindowBase.ArrangeSetBounds

* api diff

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Avalonia.Desktop.slnf

@@ -8,11 +8,11 @@
       "samples\\ControlCatalog\\ControlCatalog.csproj",
       "samples\\GpuInterop\\GpuInterop.csproj",
       "samples\\IntegrationTestApp\\IntegrationTestApp.csproj",
-      "samples\\TextTestApp\\TextTestApp.csproj",
       "samples\\MiniMvvm\\MiniMvvm.csproj",
       "samples\\RenderDemo\\RenderDemo.csproj",
       "samples\\SampleControls\\ControlSamples.csproj",
       "samples\\Sandbox\\Sandbox.csproj",
+      "samples\\TextTestApp\\TextTestApp.csproj",
       "samples\\UnloadableAssemblyLoadContext\\UnloadableAssemblyLoadContextPlug\\UnloadableAssemblyLoadContextPlug.csproj",
       "samples\\UnloadableAssemblyLoadContext\\UnloadableAssemblyLoadContext\\UnloadableAssemblyLoadContext.csproj",
       "samples\\XEmbedSample\\XEmbedSample.csproj",
@@ -29,13 +29,14 @@
       "src\\Avalonia.MicroCom\\Avalonia.MicroCom.csproj",
       "src\\Avalonia.Native\\Avalonia.Native.csproj",
       "src\\Avalonia.OpenGL\\Avalonia.OpenGL.csproj",
-      "src\\Avalonia.Vulkan\\Avalonia.Vulkan.csproj",
       "src\\Avalonia.Remote.Protocol\\Avalonia.Remote.Protocol.csproj",
       "src\\Avalonia.Themes.Fluent\\Avalonia.Themes.Fluent.csproj",
       "src\\Avalonia.Themes.Simple\\Avalonia.Themes.Simple.csproj",
+      "src\\Avalonia.Vulkan\\Avalonia.Vulkan.csproj",
       "src\\Avalonia.X11\\Avalonia.X11.csproj",
       "src\\HarfBuzz\\Avalonia.HarfBuzz\\Avalonia.HarfBuzz.csproj",
       "src\\Headless\\Avalonia.Headless.Vnc\\Avalonia.Headless.Vnc.csproj",
+      "src\\Headless\\Avalonia.Headless.XUnit\\Avalonia.Headless.XUnit.csproj",
       "src\\Headless\\Avalonia.Headless\\Avalonia.Headless.csproj",
       "src\\Linux\\Avalonia.LinuxFramebuffer\\Avalonia.LinuxFramebuffer.csproj",
       "src\\Markup\\Avalonia.Markup.Xaml.Loader\\Avalonia.Markup.Xaml.Loader.csproj",
@@ -58,6 +59,8 @@
       "tests\\Avalonia.DesignerSupport.TestApp\\Avalonia.DesignerSupport.TestApp.csproj",
       "tests\\Avalonia.DesignerSupport.Tests\\Avalonia.DesignerSupport.Tests.csproj",
       "tests\\Avalonia.Generators.Tests\\Avalonia.Generators.Tests.csproj",
+      "tests\\Avalonia.Headless.XUnit.PerAssembly.UnitTests\\Avalonia.Headless.XUnit.PerAssembly.UnitTests.csproj",
+      "tests\\Avalonia.Headless.XUnit.PerTest.UnitTests\\Avalonia.Headless.XUnit.PerTest.UnitTests.csproj",
       "tests\\Avalonia.IntegrationTests.Appium\\Avalonia.IntegrationTests.Appium.csproj",
       "tests\\Avalonia.LeakTests\\Avalonia.LeakTests.csproj",
       "tests\\Avalonia.Markup.UnitTests\\Avalonia.Markup.UnitTests.csproj",
@@ -69,4 +72,4 @@
       "tests\\TestFiles\\BuildTasks\\PInvoke\\PInvoke.csproj"
     ]
   }
-}
+}

api/Avalonia.nupkg.xml

@@ -217,6 +217,12 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Base.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Base.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.VisualTree.IHostedVisualTreeRoot</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Base.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Base.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetimeOptions</Target>
@@ -235,6 +241,12 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Diagnostics.IPopupHostProvider</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.FileDialog</Target>
@@ -289,12 +301,36 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.ChromeOverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.IPopupHost</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.Primitives.IScrollable</Target>
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.LightDismissOverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.OverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.SaveFileDialog</Target>
@@ -553,6 +589,12 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Base.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Base.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.VisualTree.IHostedVisualTreeRoot</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Base.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Base.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetimeOptions</Target>
@@ -571,6 +613,12 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Diagnostics.IPopupHostProvider</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.FileDialog</Target>
@@ -625,12 +673,36 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.ChromeOverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.IPopupHost</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.Primitives.IScrollable</Target>
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.LightDismissOverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.OverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.SaveFileDialog</Target>
@@ -1231,6 +1303,12 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>F:Avalonia.Controls.Primitives.VisualLayerManager.ChromeOverlayLayerProperty</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>F:Avalonia.Controls.TextBlock.LetterSpacingProperty</Target>
@@ -1267,6 +1345,12 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Automation.Peers.AutomationPeer.GetVisualRootCore</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.ContextMenu.get_PlacementMode</Target>
@@ -1411,18 +1495,54 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.AdornerLayer.#ctor</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.#ctor(Avalonia.Controls.Primitives.OverlayLayer)</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.ConfigurePosition(Avalonia.Visual,Avalonia.Controls.PlacementMode,Avalonia.Point,Avalonia.Controls.Primitives.PopupPositioning.PopupAnchor,Avalonia.Controls.Primitives.PopupPositioning.PopupGravity,Avalonia.Controls.Primitives.PopupPositioning.PopupPositionerConstraintAdjustment,System.Nullable{Avalonia.Rect})</Target>
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.CreatePopupHost(Avalonia.Visual,Avalonia.IAvaloniaDependencyResolver,System.Boolean)</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.CreatePopupHost(Avalonia.Visual,Avalonia.IAvaloniaDependencyResolver)</Target>
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.SetChild(Avalonia.Controls.Control)</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.TakeFocus</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.Popup.get_Host</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.Primitives.Popup.get_PlacementMode</Target>
@@ -1507,6 +1627,36 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_AdornerLayer</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_ChromeOverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_LightDismissOverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_OverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_TextSelectorLayer</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.Screens.ScreenFromWindow(Avalonia.Platform.IWindowBaseImpl)</Target>
@@ -1555,6 +1705,12 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.WindowBase.ArrangeSetBounds(Avalonia.Size)</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Platform.IWindowImpl.GetWindowsZOrder(System.Span{Avalonia.Controls.Window},System.Span{System.Int64})</Target>
@@ -2251,6 +2407,12 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>F:Avalonia.Controls.Primitives.VisualLayerManager.ChromeOverlayLayerProperty</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>F:Avalonia.Controls.TextBlock.LetterSpacingProperty</Target>
@@ -2287,6 +2449,12 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Automation.Peers.AutomationPeer.GetVisualRootCore</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.ContextMenu.get_PlacementMode</Target>
@@ -2431,18 +2599,54 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.AdornerLayer.#ctor</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.#ctor(Avalonia.Controls.Primitives.OverlayLayer)</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.ConfigurePosition(Avalonia.Visual,Avalonia.Controls.PlacementMode,Avalonia.Point,Avalonia.Controls.Primitives.PopupPositioning.PopupAnchor,Avalonia.Controls.Primitives.PopupPositioning.PopupGravity,Avalonia.Controls.Primitives.PopupPositioning.PopupPositionerConstraintAdjustment,System.Nullable{Avalonia.Rect})</Target>
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.CreatePopupHost(Avalonia.Visual,Avalonia.IAvaloniaDependencyResolver,System.Boolean)</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.CreatePopupHost(Avalonia.Visual,Avalonia.IAvaloniaDependencyResolver)</Target>
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.SetChild(Avalonia.Controls.Control)</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.OverlayPopupHost.TakeFocus</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.Popup.get_Host</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.Primitives.Popup.get_PlacementMode</Target>
@@ -2527,6 +2731,36 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_AdornerLayer</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_ChromeOverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_LightDismissOverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_OverlayLayer</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.Primitives.VisualLayerManager.get_TextSelectorLayer</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Controls.Screens.ScreenFromWindow(Avalonia.Platform.IWindowBaseImpl)</Target>
@@ -2575,6 +2809,12 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Avalonia.Controls.WindowBase.ArrangeSetBounds(Avalonia.Size)</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Avalonia.Platform.IWindowImpl.GetWindowsZOrder(System.Span{Avalonia.Controls.Window},System.Span{System.Int64})</Target>
@@ -2809,6 +3049,12 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Base.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Base.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0006</DiagnosticId>
+    <Target>P:Avalonia.Input.IInputRoot.FocusRoot</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Base.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Base.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0006</DiagnosticId>
     <Target>P:Avalonia.Platform.ILockedFramebuffer.AlphaFormat</Target>
@@ -3013,6 +3259,12 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Base.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Base.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0006</DiagnosticId>
+    <Target>P:Avalonia.Input.IInputRoot.FocusRoot</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Base.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Base.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0006</DiagnosticId>
     <Target>P:Avalonia.Platform.ILockedFramebuffer.AlphaFormat</Target>
@@ -3493,6 +3745,24 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Base.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Base.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0009</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.AdornerLayer</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0009</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.OverlayPopupHost</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0009</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.VisualLayerManager</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0009</DiagnosticId>
     <Target>T:Avalonia.Platform.Screen</Target>
@@ -3511,6 +3781,24 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Base.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Base.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0009</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.AdornerLayer</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0009</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.OverlayPopupHost</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0009</DiagnosticId>
+    <Target>T:Avalonia.Controls.Primitives.VisualLayerManager</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0009</DiagnosticId>
     <Target>T:Avalonia.Platform.Screen</Target>

src/Avalonia.Base/Input/FocusManager.cs

@@ -246,10 +246,10 @@ namespace Avalonia.Input
             if (scope is not Visual v)
                 return null;
 
-            var root = v.VisualRoot as Visual;
+            var root = v.PresentationSource?.InputRoot.FocusRoot as Visual;
 
             while (root is IHostedVisualTreeRoot hosted &&
-                hosted.Host?.VisualRoot is Visual parentRoot)
+                hosted.Host?.PresentationSource?.InputRoot.FocusRoot is {} parentRoot)
             {
                 root = parentRoot;
             }

src/Avalonia.Base/Input/IInputRoot.cs

@@ -26,5 +26,12 @@ namespace Avalonia.Input
         internal ITextInputMethodImpl? InputMethod { get; }
         
         internal InputElement RootElement { get; }
+        
+        // HACK: This is a temporary hack for "default focus" concept. 
+        // If nothing is focused we send keyboard events to Window. Since for now we always
+        // control PresentationSource, we simply pass the TopLevel as a separate parameter there.
+        // It's also currently used by automation since we have special WindowAutomationPeer which needs to target the
+        // window itself
+        public InputElement FocusRoot { get; }
     }
 }

src/Avalonia.Base/Input/KeyboardDevice.cs

@@ -225,7 +225,7 @@ namespace Avalonia.Input
             if(e.Handled)
                 return;
 
-            var element = FocusedElement ?? e.Root.RootElement;
+            var element = FocusedElement ?? e.Root.FocusRoot;
 
             if (e is RawKeyEventArgs keyInput)
             {

src/Avalonia.Base/VisualTree/IHostedVisualTreeRoot.cs

@@ -3,7 +3,7 @@ namespace Avalonia.VisualTree
     /// <summary>
     /// Interface for controls that are at the root of a hosted visual tree, such as popups.
     /// </summary>
-    public interface IHostedVisualTreeRoot
+    internal interface IHostedVisualTreeRoot
     {
         /// <summary>
         /// Gets the visual tree host.

src/Avalonia.Controls/Automation/Peers/AutomationPeer.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Avalonia.Automation.Provider;
+using Avalonia.Metadata;
 
 namespace Avalonia.Automation.Peers
 {
@@ -398,13 +399,25 @@ namespace Avalonia.Automation.Peers
         ///     <term>Windows</term>
         ///     <description>No mapping, but used internally to translate coordinates.</description>
         ///   </item>
+        /// </list>
+        /// </remarks>
+        [PrivateApi]
+        public AutomationPeer? GetVisualRoot() => GetVisualRootCore();
+
+        /// <summary>
+        /// Gets the <see cref="AutomationPeer"/> that is the root of this <see cref="AutomationPeer"/>'s
+        /// visual tree.
+        /// </summary>
+        /// <remarks>
+        /// <list type="table">
         ///   <item>
         ///     <term>macOS</term>
         ///     <description><c>NSAccessibilityProtocol.accessibilityTopLevelUIElement</c></description>
         ///   </item>
         /// </list>
         /// </remarks>
-        public AutomationPeer? GetVisualRoot() => GetVisualRootCore();
+        [PrivateApi]
+        public AutomationPeer? GetAutomationRoot() => GetAutomationRootCore();
 
         /// <summary>
         /// Gets a value that indicates whether the element that is associated with this automation
@@ -633,7 +646,7 @@ namespace Avalonia.Automation.Peers
             return GetAutomationControlTypeCore();
         }
 
-        protected virtual AutomationPeer? GetVisualRootCore()
+        private protected virtual AutomationPeer? GetAutomationRootCore()
         {
             var peer = this;
             var parent = peer.GetParent();
@@ -647,6 +660,8 @@ namespace Avalonia.Automation.Peers
             return peer;
         }
 
+        private protected virtual AutomationPeer? GetVisualRootCore() => GetAutomationRootCore();
+
 
         protected virtual bool IsContentElementOverrideCore()
         {

src/Avalonia.Controls/Automation/Peers/ControlAutomationPeer.cs

@@ -147,10 +147,10 @@ namespace Avalonia.Automation.Peers
             EnsureConnected();
             return _parent;
         }
-
-        protected override AutomationPeer? GetVisualRootCore()
+        
+        private protected override AutomationPeer? GetVisualRootCore()
         {
-            if (Owner.GetVisualRoot() is Control c)
+            if (Owner?.PresentationSource?.InputRoot?.FocusRoot is Control c)
                 return CreatePeerForElement(c);
             return null;
         }
@@ -268,11 +268,13 @@ namespace Avalonia.Automation.Peers
 
         private void VisualChildrenChanged(object? sender, EventArgs e) => InvalidateChildren();
 
+        private protected virtual Visual? GetVisualParent() => Owner.GetVisualParent();
+
         private void OwnerPropertyChanged(object? sender, AvaloniaPropertyChangedEventArgs e)
         {
             if (e.Property == Visual.IsVisibleProperty)
             {
-                var parent = Owner.GetVisualParent();
+                var parent = GetVisualParent();
                 if (parent is Control c)
                     (GetOrCreate(c) as ControlAutomationPeer)?.InvalidateChildren();
             }
@@ -303,7 +305,7 @@ namespace Avalonia.Automation.Peers
         {
             if (!_parentValid)
             {
-                var parent = Owner.GetVisualParent();
+                var parent = GetVisualParent();
 
                 while (parent is object)
                 {
@@ -311,6 +313,11 @@ namespace Avalonia.Automation.Peers
                     {
                         var parentPeer = GetOrCreate(c);
                         parentPeer.GetChildren();
+                        if (parentPeer is ControlAutomationPeer controlPeer)
+                        {
+                            parent = controlPeer.GetVisualParent();
+                            continue;
+                        }
                     }
 
                     parent = parent.GetVisualParent();

src/Avalonia.Controls/Automation/Peers/EmbeddableControlRootAutomationPeer.cs

@@ -58,8 +58,8 @@ namespace Avalonia.Controls.Automation.Peers
         {
             var oldFocus = _focus;
             var c = focus as Control;
-
-            _focus = c?.VisualRoot == Owner ? c : null;
+            
+            _focus = Owner.IsVisualAncestorOf(c) ? c : null;
 
             if (_focus != oldFocus)
             {
@@ -89,5 +89,7 @@ namespace Avalonia.Controls.Automation.Peers
             Owner.Closed -= OnClosed;
             StopTrackingFocus();
         }
+
+        private protected override Visual? GetVisualParent() => null;
     }
 }

src/Avalonia.Controls/Automation/Peers/WindowBaseAutomationPeer.cs

@@ -70,7 +70,7 @@ namespace Avalonia.Automation.Peers
             var oldFocus = _focus;
             var c = focus as Control;
             
-            _focus = c?.VisualRoot == Owner ? c : null;
+            _focus = Owner.IsVisualAncestorOf(c) ? c : null;
             
             if (_focus != oldFocus)
             {
@@ -88,6 +88,11 @@ namespace Avalonia.Automation.Peers
                 OnFocusChanged(KeyboardDevice.Instance!.FocusedElement);
             }
         }
+
+        private protected override Visual? GetVisualParent()
+        {
+            return null;
+        }
     }
 }
 

src/Avalonia.Controls/Diagnostics/IPopupHostProvider.cs

@@ -8,7 +8,7 @@ namespace Avalonia.Controls.Diagnostics
     /// Diagnostics interface to retrieve an associated <see cref="IPopupHost"/>.
     /// </summary>
     [NotClientImplementable]
-    public interface IPopupHostProvider
+    internal interface IPopupHostProvider
     {
         /// <summary>
         /// The popup host.

src/Avalonia.Controls/PresentationSource/PresentationSource.Input.cs

@@ -57,4 +57,6 @@ internal partial class PresentationSource
         }
         return candidate;
     }
+    
+    public InputElement FocusRoot { get; }
 }

src/Avalonia.Controls/PresentationSource/PresentationSource.cs

@@ -19,7 +19,8 @@ internal partial class PresentationSource : IPresentationSource, IInputRoot, IDi
 
     internal FocusManager FocusManager { get; } = new();
 
-    public PresentationSource(InputElement rootVisual, ITopLevelImpl platformImpl,
+    public PresentationSource(InputElement rootVisual, InputElement defaultFocusVisual,
+        ITopLevelImpl platformImpl,
         IAvaloniaDependencyResolver dependencyResolver, Func<Size> clientSizeProvider)
     {
         _clientSizeProvider = clientSizeProvider;
@@ -41,6 +42,7 @@ internal partial class PresentationSource : IPresentationSource, IInputRoot, IDi
         LayoutManager = CreateLayoutManager();
         
         RootVisual = rootVisual;
+        FocusRoot = defaultFocusVisual;
     }
 
     // In WPF it's a Visual and it's nullable. For now we have it as non-nullable InputElement since 

src/Avalonia.Controls/Primitives/AdornerLayer.cs

@@ -12,7 +12,6 @@ namespace Avalonia.Controls.Primitives
     /// Adorners are always on top of the adorned element and are positioned to stay relative to the adorned element.
     /// </summary>
     /// <remarks>
-    /// TODO: Need to track position of adorned elements and move the adorner if they move.
     /// </remarks>
     public class AdornerLayer : Canvas
     {
@@ -55,7 +54,7 @@ namespace Avalonia.Controls.Primitives
             IsClipEnabledProperty.Changed.Subscribe(AdornerIsClipEnabledChanged);
         }
 
-        public AdornerLayer()
+        internal AdornerLayer()
         {
             Children.CollectionChanged += ChildrenCollectionChanged;
             _trackingHelper.SetVisual(this);

src/Avalonia.Controls/Primitives/ChromeOverlayLayer.cs

@@ -4,27 +4,8 @@ using Avalonia.VisualTree;
 
 namespace Avalonia.Controls.Primitives
 {
-    public class ChromeOverlayLayer : Panel
+    internal class ChromeOverlayLayer : Panel
     {
-        public static Panel? GetOverlayLayer(Visual visual)
-        {
-            foreach (var v in visual.GetVisualAncestors())
-                if (v is VisualLayerManager vlm)
-                    if (vlm.OverlayLayer != null)
-                        return vlm.ChromeOverlayLayer;
 
-            if (visual is TopLevel tl)
-            {
-                var layers = tl.GetVisualDescendants().OfType<VisualLayerManager>().FirstOrDefault();
-                return layers?.ChromeOverlayLayer;
-            }
-
-            return null;
-        }
-
-        public void Add(Control c)
-        {
-            base.Children.Add(c);
-        }
     }
 }

src/Avalonia.Controls/Primitives/IPopupHost.cs

@@ -15,8 +15,7 @@ namespace Avalonia.Controls.Primitives
     /// (<see cref="PopupRoot"/>) or an <see cref="OverlayPopupHost"/> which is created
     /// on an <see cref="OverlayLayer"/>.
     /// </remarks>
-    [PrivateApi]
-    public interface IPopupHost : IDisposable, IFocusScope
+    internal interface IPopupHost : IDisposable, IFocusScope
     {
         /// <summary>
         /// Gets or sets the fixed width of the popup.

src/Avalonia.Controls/Primitives/LightDismissOverlayLayer.cs

@@ -12,7 +12,7 @@ namespace Avalonia.Controls.Primitives
     /// <summary>
     /// A layer that is used to dismiss a <see cref="Popup"/> when the user clicks outside.
     /// </summary>
-    public class LightDismissOverlayLayer : Border, ICustomHitTest
+    internal class LightDismissOverlayLayer : Border, ICustomHitTest
     {
         public IInputElement? InputPassThroughElement { get; set; }
 

src/Avalonia.Controls/Primitives/OverlayLayer.cs

@@ -4,7 +4,7 @@ using Avalonia.VisualTree;
 
 namespace Avalonia.Controls.Primitives
 {
-    public class OverlayLayer : Canvas
+    internal class OverlayLayer : Canvas
     {
         protected override bool BypassFlowDirectionPolicies => true;
         public Size AvailableSize { get; private set; }

src/Avalonia.Controls/Primitives/OverlayPopupHost.cs

@@ -31,7 +31,7 @@ namespace Avalonia.Controls.Primitives
         static OverlayPopupHost()
             => KeyboardNavigation.TabNavigationProperty.OverrideDefaultValue<OverlayPopupHost>(KeyboardNavigationMode.Cycle);
 
-        public OverlayPopupHost(OverlayLayer overlayLayer)
+        internal OverlayPopupHost(OverlayLayer overlayLayer)
         {
             _overlayLayer = overlayLayer;
             _positioner = new ManagedPopupPositioner(this);
@@ -41,7 +41,7 @@ namespace Avalonia.Controls.Primitives
 
         /// <inheritdoc />
         [System.Diagnostics.CodeAnalysis.SuppressMessage("AvaloniaProperty", "AVP1012", Justification = "Explicit set")]
-        public void SetChild(Control? control)
+        void IPopupHost.SetChild(Control? control)
         {
             Content = control;
         }
@@ -86,7 +86,7 @@ namespace Avalonia.Controls.Primitives
             _overlayLayer.Children.Remove(this);
         }
 
-        public void TakeFocus()
+        void IPopupHost.TakeFocus()
         {
             // Nothing to do here: overlay popups are implemented inside the window.
         }
@@ -150,9 +150,8 @@ namespace Avalonia.Controls.Primitives
         }
 
         double IManagedPopupPositionerPopup.Scaling => 1;
-
-        [PrivateApi]
-        public static IPopupHost CreatePopupHost(Visual target, IAvaloniaDependencyResolver? dependencyResolver, bool shouldUseOverlayLayer)
+        
+        internal static IPopupHost CreatePopupHost(Visual target, IAvaloniaDependencyResolver? dependencyResolver, bool shouldUseOverlayLayer)
         {
             if (!shouldUseOverlayLayer)
             {

src/Avalonia.Controls/Primitives/Popup.cs

@@ -176,7 +176,7 @@ namespace Avalonia.Controls.Primitives
 
         internal event EventHandler<CancelEventArgs>? Closing;
 
-        public IPopupHost? Host => _openState?.PopupHost;
+        internal IPopupHost? Host => _openState?.PopupHost;
 
         /// <summary>
         /// Gets or sets a hint to the window manager that a shadow should be added to the popup.

src/Avalonia.Controls/Primitives/PopupRoot.cs

@@ -190,7 +190,7 @@ namespace Avalonia.Controls.Primitives
             return new Size(width, height);
         }
 
-        protected sealed override Size ArrangeSetBounds(Size size)
+        private protected sealed override Size ArrangeSetBounds(Size size)
         {
             if (_popupSize != size)
             {

src/Avalonia.Controls/Primitives/VisualLayerManager.cs

@@ -1,9 +1,10 @@
 using System.Collections.Generic;
+using Avalonia.Controls.Chrome;
 using Avalonia.LogicalTree;
 
 namespace Avalonia.Controls.Primitives
 {
-    public class VisualLayerManager : Decorator
+    public sealed class VisualLayerManager : Decorator
     {
         private const int AdornerZIndex = int.MaxValue - 100;
         private const int ChromeZIndex = int.MaxValue - 99;
@@ -14,12 +15,9 @@ namespace Avalonia.Controls.Primitives
         private ILogicalRoot? _logicalRoot;
         private readonly List<Control> _layers = new();
 
-        public static readonly StyledProperty<ChromeOverlayLayer?> ChromeOverlayLayerProperty =
-            AvaloniaProperty.Register<VisualLayerManager, ChromeOverlayLayer?>(nameof(ChromeOverlayLayer));
-
         public bool IsPopup { get; set; }
 
-        public AdornerLayer AdornerLayer
+        internal AdornerLayer AdornerLayer
         {
             get
             {
@@ -30,30 +28,43 @@ namespace Avalonia.Controls.Primitives
             }
         }
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("AvaloniaProperty", "AVP1030")]
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("AvaloniaProperty", "AVP1031",
-            Justification = "A hack to make ChromeOverlayLayer lazily creatable. It is expected that GetValue(ChromeOverlayLayerProperty) alone won't work.")]
-        public ChromeOverlayLayer ChromeOverlayLayer
-        {
-            get
-            {
-                var current = GetValue(ChromeOverlayLayerProperty);
 
-                if (current is null)
-                {
-                    var chromeOverlayLayer = new ChromeOverlayLayer();
-                    AddLayer(chromeOverlayLayer, ChromeZIndex);
+        protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
+        {
+            EnsureChromeOverlayIfNeeded();
+            
+            base.OnAttachedToVisualTree(e);
+        }
 
-                    SetValue(ChromeOverlayLayerProperty, chromeOverlayLayer);
+        void EnsureChromeOverlayIfNeeded()
+        {
+            // HACK: This is a replacement hack for the old set of hacks for TitleBar.
 
-                    current = chromeOverlayLayer;
+            // Check if we are attached direclty-ish to a Window (i. e. no other VisualLayerManager in between).
+            // If we are, then we are the "main" VisualLayerManager and should create the ChromeOverlayLayer and add titlebar there
+            var parent = VisualParent;
+            while (parent != null)
+            {
+                if(parent is VisualLayerManager)
+                    break;
+                else if (parent is Window window)
+                {
+                    if (FindLayer<ChromeOverlayLayer>() == null)
+                    {
+                        var layer = new ChromeOverlayLayer();
+                        AddLayer(layer, ChromeZIndex);
+                        layer.Children.Add(new TitleBar());
+                    }
+                    
+                    break;
                 }
 
-                return current;
+                parent = parent.VisualParent;
+
             }
         }
-
-        public OverlayLayer? OverlayLayer
+        
+        internal OverlayLayer? OverlayLayer
         {
             get
             {
@@ -66,7 +77,7 @@ namespace Avalonia.Controls.Primitives
             }
         }
 
-        public TextSelectorLayer? TextSelectorLayer
+        internal TextSelectorLayer? TextSelectorLayer
         {
             get
             {
@@ -79,7 +90,7 @@ namespace Avalonia.Controls.Primitives
             }
         }
 
-        public LightDismissOverlayLayer LightDismissOverlayLayer
+        internal LightDismissOverlayLayer LightDismissOverlayLayer
         {
             get
             {

src/Avalonia.Controls/ToolTipService.cs

@@ -38,7 +38,7 @@ namespace Avalonia.Controls
             if (e is RawPointerEventArgs pointerEvent)
             {
                 bool isTooltipEvent = false;
-                if (_tipControl?.GetValue(ToolTip.ToolTipProperty) is { } currentTip && e.Root.RootElement == currentTip.PopupHost)
+                if (_tipControl?.GetValue(ToolTip.ToolTipProperty) is { } currentTip && e.Root == (currentTip.PopupHost as Visual)?.GetInputRoot())
                 {
                     isTooltipEvent = true;
                     _lastTipEventTime = pointerEvent.Timestamp;

src/Avalonia.Controls/TopLevel.cs

@@ -189,8 +189,12 @@ namespace Avalonia.Controls
             PlatformImpl = impl ?? throw new InvalidOperationException(
                 "Could not create window implementation: maybe no windowing subsystem was initialized?");
             dependencyResolver ??= AvaloniaLocator.Current;
-            _source = new PresentationSource(this, impl, dependencyResolver, () => ClientSize);
-            _source.RootVisual = this;
+
+            var hostVisual = new TopLevelHost(this);
+            ((ISetLogicalParent)hostVisual).SetParent(this);
+
+            _source = new PresentationSource(hostVisual, this,
+                impl, dependencyResolver, () => ClientSize);
             _source.Renderer.SceneInvalidated += SceneInvalidated;
 
             _scaling = ValidateScaling(impl.RenderScaling);

src/Avalonia.Controls/TopLevelHost.cs

@@ -0,0 +1,21 @@
+using Avalonia.Input;
+
+namespace Avalonia.Controls;
+
+/// <summary>
+/// For now this is a stub class that is needed to prevent people from assuming that TopLevel sits at the root of the
+/// visual tree.
+/// In future 12.x releases it will serve more roles like hosting popups and CSD.
+/// </summary>
+internal class TopLevelHost : Control
+{
+    static TopLevelHost()
+    {
+        KeyboardNavigation.TabNavigationProperty.OverrideDefaultValue<TopLevelHost>(KeyboardNavigationMode.Cycle);
+    }
+
+    public TopLevelHost(TopLevel tl)
+    {
+        VisualChildren.Add(tl);
+    }
+}

src/Avalonia.Controls/Window.cs

@@ -1164,7 +1164,7 @@ namespace Avalonia.Controls
             return result;
         }
 
-        protected sealed override Size ArrangeSetBounds(Size size)
+        private protected sealed override Size ArrangeSetBounds(Size size)
         {
             _arrangeBounds = size;
             if (_canHandleResized)

src/Avalonia.Controls/WindowBase.cs

@@ -200,6 +200,7 @@ namespace Avalonia.Controls
 
             if (change.Property == IsVisibleProperty)
             {
+                VisualRoot?.IsVisible = change.GetNewValue<bool>();
                 IsVisibleChanged(change);
             }
         }
@@ -311,7 +312,7 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="size">The requested size of the window.</param>
         /// <returns>The actual size of the window.</returns>
-        protected virtual Size ArrangeSetBounds(Size size) => size;
+        private protected virtual Size ArrangeSetBounds(Size size) => size;
 
         /// <summary>
         /// Handles a window position change notification from 

src/Avalonia.Native/AvnAutomationPeer.cs

@@ -50,7 +50,7 @@ namespace Avalonia.Native
         public AvnLandmarkType LandmarkType => (AvnLandmarkType?)_inner.GetLandmarkType() ?? AvnLandmarkType.LandmarkNone;
         public int HeadingLevel => _inner.GetHeadingLevel();
         public IAvnAutomationPeer? Parent => Wrap(_inner.GetParent());
-        public IAvnAutomationPeer? VisualRoot => Wrap(_inner.GetVisualRoot());
+        public IAvnAutomationPeer? VisualRoot => Wrap(_inner.GetAutomationRoot());
         public AvnLiveSetting LiveSetting => (AvnLiveSetting)_inner.GetLiveSetting();
 
         public int HasKeyboardFocus() => _inner.HasKeyboardFocus().AsComBool();

src/Avalonia.Native/TopLevelImpl.cs

@@ -169,7 +169,7 @@ internal class TopLevelImpl : ITopLevelImpl, IFramebufferPlatformSurface
 
     public AutomationPeer? GetAutomationPeer()
     {
-        return _inputRoot?.RootElement is Control c ? ControlAutomationPeer.CreatePeerForElement(c) : null;
+        return _inputRoot?.FocusRoot is Control c ? ControlAutomationPeer.CreatePeerForElement(c) : null;
     }
 
     public bool RawTextInputEvent(ulong timeStamp, string text)

src/Avalonia.Themes.Fluent/Controls/Window.xaml

@@ -15,9 +15,6 @@
           <Border Background="{TemplateBinding Background}" IsHitTestVisible="False" />
           <Panel Background="Transparent" Margin="{TemplateBinding WindowDecorationMargin}" />
           <VisualLayerManager>
-            <VisualLayerManager.ChromeOverlayLayer>
-              <TitleBar />
-            </VisualLayerManager.ChromeOverlayLayer>
             <ContentPresenter Name="PART_ContentPresenter"
                               ContentTemplate="{TemplateBinding ContentTemplate}"
                               Content="{TemplateBinding Content}"

src/Avalonia.Themes.Simple/Controls/Window.xaml

@@ -18,9 +18,6 @@
           <Panel Margin="{TemplateBinding WindowDecorationMargin}"
                  Background="Transparent" />
           <VisualLayerManager>
-            <VisualLayerManager.ChromeOverlayLayer>
-              <TitleBar />
-            </VisualLayerManager.ChromeOverlayLayer>
             <ContentPresenter Name="PART_ContentPresenter"
                               Margin="{TemplateBinding Padding}"
                               HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"

src/Avalonia.X11/X11Window.cs

@@ -268,8 +268,8 @@ namespace Avalonia.X11
                     : Task.FromResult<IStorageProvider?>(null),
                 () => GtkSystemDialog.TryCreate(this),
                 // TODO: This will be incompatible with "root element is not a TopLevel" scenarios,
-                // we should probably have a separate API for this
-                () => Task.FromResult(InputRoot.RootElement is TopLevel tl
+                // HACK: this relies on focus root being TopLevel which currently is true
+                () => Task.FromResult(InputRoot.FocusRoot is TopLevel tl
                     ? (IStorageProvider?)new ManagedStorageProvider(tl)
                     : null)
             });

src/Windows/Avalonia.Win32.Automation/AutomationNode.cs

@@ -11,6 +11,7 @@ using Avalonia.Automation;
 using Avalonia.Automation.Peers;
 using Avalonia.Controls.Automation.Peers;
 using Avalonia.Threading;
+using Avalonia.VisualTree;
 using Avalonia.Win32.Automation.Interop;
 using AAP = Avalonia.Automation.Provider;
 using UIA = Avalonia.Win32.Automation.Interop;
@@ -83,8 +84,14 @@ namespace Avalonia.Win32.Automation
         {
             return InvokeSync(() =>
             {
-                if (GetRoot() is RootAutomationNode root)
-                    return root.ToScreen(Peer.GetBoundingRectangle());
+                if (Peer.GetVisualRoot() is ControlAutomationPeer root &&
+                    root.Owner.GetPresentationSource() is not null)
+                {
+                    var originalRect = Peer.GetBoundingRectangle();
+                    return new PixelRect(root.Owner.PointToScreen(originalRect.TopLeft),
+                        root.Owner.PointToScreen(originalRect.BottomRight)).ToRect(1);
+                }
+
                 return default;
             });
         }
@@ -287,7 +294,7 @@ namespace Avalonia.Win32.Automation
         private RootAutomationNode? GetRoot()
         {
             Dispatcher.UIThread.VerifyAccess();
-            return GetOrCreate(Peer.GetVisualRoot()) as RootAutomationNode;
+            return GetOrCreate(Peer.GetAutomationRoot()) as RootAutomationNode;
         }
 
         private void OnPeerChildrenChanged(object? sender, EventArgs e)

src/Windows/Avalonia.Win32.Automation/RootAutomationNode.cs

@@ -48,16 +48,6 @@ namespace Avalonia.Win32.Automation
             return GetOrCreate(focus);
         }
 
-        public Rect ToScreen(Rect rect)
-        {
-            if (WindowImpl is null)
-                return default;
-            return new PixelRect(
-                    WindowImpl.PointToScreen(rect.TopLeft),
-                    WindowImpl.PointToScreen(rect.BottomRight))
-                .ToRect(1);
-        }
-
         public override IRawElementProviderSimple? GetHostRawElementProvider()
         {
             var handle = WindowImpl?.Handle?.Handle ?? IntPtr.Zero;

src/Windows/Avalonia.Win32/WindowImpl.AppWndProc.cs

@@ -937,7 +937,7 @@ namespace Avalonia.Win32
                         return IntPtr.Zero;
                     }
                 case WindowsMessage.WM_GETOBJECT:
-                    if ((long)lParam == uiaRootObjectId && UiaCoreTypesApi.IsNetComInteropAvailable && _owner?.RootElement is Control control)
+                    if ((long)lParam == uiaRootObjectId && UiaCoreTypesApi.IsNetComInteropAvailable && _owner?.FocusRoot is Control control)
                     {
                         var peer = ControlAutomationPeer.CreatePeerForElement(control);
                         var node = AutomationNode.GetOrCreate(peer);

tests/Avalonia.Base.UnitTests/Rendering/CompositorInvalidationClippingTests.cs

@@ -14,6 +14,8 @@ public class CompositorInvalidationClippingTests : CompositorTestsBase
         foreach (var child in visual.VisualChildren) count += CountVisuals(child);
         return count;
     }
+
+    private const int TopLevelOverhead = 2; // TopLevel + TopLevelHost
     
     [Theory,
         // If canvas itself has no background, the second render won't draw any visuals at all, since
@@ -22,9 +24,9 @@ public class CompositorInvalidationClippingTests : CompositorTestsBase
         InlineData(true, false, false, 1, 0),
         InlineData(false, true, false, 1, 0),
         // If canvas has background, the second render will draw only the canvas visual itself
-        InlineData(false, false, true, 5, 4),
-        InlineData(true, false,   true,5, 4),
-        InlineData(false, true,  true, 5, 4),
+        InlineData(false, false, true, 4 + TopLevelOverhead, 3 + TopLevelOverhead),
+        InlineData(true, false,   true,4 + TopLevelOverhead, 3 + TopLevelOverhead),
+        InlineData(false, true,  true, 4 + TopLevelOverhead, 3 + TopLevelOverhead),
     ]
     public void Do_Not_Re_Render_Unaffected_Visual_Trees(bool clipToBounds, bool clipGeometry,
         bool canvasHasContent,

tests/Avalonia.Controls.UnitTests/FlyoutTests.cs

@@ -256,7 +256,7 @@ namespace Avalonia.Controls.UnitTests
                 var hitTester = new Mock<IHitTester>();
                 window.HitTesterOverride = hitTester.Object;
                 hitTester.Setup(x =>
-                    x.HitTestFirst(new Point(90, 90), window, It.IsAny<Func<Visual, bool>>()))
+                    x.HitTestFirst(new Point(90, 90), (Visual)window.VisualRoot!, It.IsAny<Func<Visual, bool>>()))
                     .Returns(button);
 
                 var e = CreatePointerPressedEventArgs(window, new Point(90, 90));
@@ -299,7 +299,7 @@ namespace Avalonia.Controls.UnitTests
                 var hitTester = new Mock<IHitTester>();
                 window.HitTesterOverride = hitTester.Object;
                 hitTester.Setup(x =>
-                    x.HitTestFirst(new Point(90, 90), window, It.IsAny<Func<Visual, bool>>()))
+                    x.HitTestFirst(new Point(90, 90), (Visual)window.VisualRoot!, It.IsAny<Func<Visual, bool>>()))
                     .Returns(button);
 
                 var e = CreatePointerPressedEventArgs(window, new Point(90, 90));

tests/Avalonia.Controls.UnitTests/Primitives/PopupRootTests.cs

@@ -100,7 +100,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
         }
         
         [Fact]
-        public void PopupRoot_Should_Have_Null_VisualParent()
+        public void PopupRoot_Should_Have_TopLevelHost_VisualParent()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
             {
@@ -108,7 +108,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
 
                 target.Open();
 
-                Assert.Null(((Visual)target.Host!).GetVisualParent());
+                Assert.IsType<TopLevelHost>(((Visual)target.Host!).GetVisualParent());
             }
         }
         

tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs

@@ -607,7 +607,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
                 window.Content = border;
 
                 hitTester.Setup(x =>
-                    x.HitTestFirst(new Point(10, 15), window, It.IsAny<Func<Visual, bool>>()))
+                    x.HitTestFirst(new Point(10, 15), (Visual)window.VisualRoot!, It.IsAny<Func<Visual, bool>>()))
                     .Returns(border);
 
                 border.PointerPressed += (s, e) =>

tests/Avalonia.Controls.UnitTests/ToolTipTests.cs

@@ -26,7 +26,7 @@ namespace Avalonia.Controls.UnitTests
             var toolTip = control.GetValue(ToolTip.ToolTipProperty);
             Assert.NotNull(toolTip);
             Assert.IsType<PopupRoot>(toolTip.PopupHost);
-            Assert.Same(toolTip.VisualRoot, toolTip.PopupHost);
+            Assert.Same(TopLevel.GetTopLevel(toolTip), toolTip.PopupHost);
         }
     }
 
@@ -574,7 +574,7 @@ namespace Avalonia.Controls.UnitTests
                     point = new Point(id, int.MaxValue);
                 }
 
-                hitTesterMock.Setup(m => m.HitTestFirst(point, window, It.IsAny<Func<Visual, bool>>()))
+                hitTesterMock.Setup(m => m.HitTestFirst(point, It.IsAny<Visual>(), It.IsAny<Func<Visual, bool>>()))
                     .Returns(control);
 
                 var root = control?.GetInputRoot() ?? window.InputRoot;
@@ -585,7 +585,7 @@ namespace Avalonia.Controls.UnitTests
 
                 if (lastRoot != null && lastRoot != root)
                 {
-                    ((TopLevel)lastRoot.RootElement)?.PlatformImpl?.Input?.Invoke(new RawPointerEventArgs(s_mouseDevice, timestamp,
+                    ((PresentationSource)lastRoot)?.PlatformImpl?.Input?.Invoke(new RawPointerEventArgs(s_mouseDevice, timestamp,
                         lastRoot, RawPointerEventType.LeaveWindow, new Point(-1,-1), RawInputModifiers.None));
                 }
 

tests/Avalonia.Controls.UnitTests/TopLevelTests.cs

@@ -222,7 +222,7 @@ namespace Avalonia.Controls.UnitTests
         }
 
         [Fact]
-        public void Adding_Top_Level_As_Child_Should_Not_Exception()
+        public void Adding_Top_Level_As_Child_Should_Throw_Exception()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
             {
@@ -233,8 +233,7 @@ namespace Avalonia.Controls.UnitTests
                 target.Template = CreateTemplate();
                 target.Content = child;
                 target.ApplyTemplate();
-
-                target.Presenter!.ApplyTemplate();
+                Assert.Throws<InvalidOperationException>(() => target.Presenter!.ApplyTemplate());
             }
         }
 

tests/Avalonia.Headless.UnitTests/RenderingTests.cs

@@ -4,6 +4,7 @@ using Avalonia.Controls;
 using Avalonia.Layout;
 using Avalonia.Media;
 using Avalonia.Rendering.Composition;
+using Avalonia.Threading;
 
 namespace Avalonia.Headless.UnitTests;
 
@@ -159,6 +160,8 @@ public class RenderingTests
 
         window.Show();
 
+        Dispatcher.UIThread.RunJobs();
+
         var compositionVisual = ElementComposition.GetElementVisual(window)!;
         var snapshot = await compositionVisual.Compositor.CreateCompositionVisualSnapshot(compositionVisual, 1);
 

tests/Avalonia.RenderTests/TestRenderRoot.cs

@@ -75,6 +75,6 @@ namespace Avalonia.Skia.RenderTests
         public IInputElement? PointerOverElement { get; set; }
         public ITextInputMethodImpl? InputMethod { get; }
         public InputElement RootElement => this;
-
+        public InputElement FocusRoot => this;
     }
 }

tests/Avalonia.UnitTests/TestRoot.cs

@@ -80,6 +80,7 @@ namespace Avalonia.UnitTests
         public IInputElement? PointerOverElement { get; set; }
         public ITextInputMethodImpl? InputMethod { get; }
         public InputElement RootElement => this;
+        public InputElement FocusRoot => this;
 
         public bool ShowAccessKeys { get; set; }