diff --git a/Avalonia.sln b/Avalonia.sln
index ccaa41f552..ffd7b4d4f4 100644
--- a/Avalonia.sln
+++ b/Avalonia.sln
@@ -150,6 +150,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Props", "Props", "{F3AC8BC1
 		build\System.Memory.props = build\System.Memory.props
 		build\UnitTests.NetFX.props = build\UnitTests.NetFX.props
 		build\XUnit.props = build\XUnit.props
+		build\ApiDiff.props = build\ApiDiff.props
 	EndProjectSection
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Targets", "Targets", "{4D6FAF79-58B4-482F-9122-0668C346364C}"
diff --git a/NuGet.Config b/NuGet.Config
index 2a1e0af74d..3abd236d42 100644
--- a/NuGet.Config
+++ b/NuGet.Config
@@ -1,7 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
+
 <configuration>
   <packageSources>
     <clear />
     <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
+      <add key="dotnet-eng" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-eng/nuget/v3/index.json" />
   </packageSources>
 </configuration>
diff --git a/build/ApiDiff.props b/build/ApiDiff.props
new file mode 100644
index 0000000000..1573dc2dd6
--- /dev/null
+++ b/build/ApiDiff.props
@@ -0,0 +1,12 @@
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <ApiContractPackageVersion>0.10.0-preview2</ApiContractPackageVersion>
+    <NugetPackageName Condition="'$(PackageId)' != ''">$(PackageId)</NugetPackageName>
+    <NugetPackageName Condition="'$(PackageId)' == ''">Avalonia</NugetPackageName>
+  </PropertyGroup>
+    <ItemGroup>
+      <PackageDownload Include="$(NugetPackageName)" Version="[$(ApiContractPackageVersion)]" />
+      <PackageReference Include="Microsoft.DotNet.ApiCompat" Version="5.0.0-beta.20372.2" PrivateAssets="All" />
+    <ResolvedMatchingContract Include="$(NuGetPackageRoot)\$(NugetPackageName.ToLower())\$(ApiContractPackageVersion)\lib\$(TargetFramework)\$(AssemblyName).dll" />
+    </ItemGroup>
+</Project>
diff --git a/samples/ControlCatalog/Pages/MenuPage.xaml b/samples/ControlCatalog/Pages/MenuPage.xaml
index de9ea34e80..e9d2301e89 100644
--- a/samples/ControlCatalog/Pages/MenuPage.xaml
+++ b/samples/ControlCatalog/Pages/MenuPage.xaml
@@ -20,7 +20,9 @@
                         <Separator/>
                         <MenuItem Header="Menu with _Submenu">
                             <MenuItem Header="Submenu _1"/>
-                            <MenuItem Header="Submenu _2"/>
+                            <MenuItem Header="Submenu _2 with Submenu">
+                                <MenuItem Header="Submenu Level 2" />
+                            </MenuItem>
                         </MenuItem>
                         <MenuItem Header="Menu Item with _Icon" InputGesture="Ctrl+Shift+B">
                             <MenuItem.Icon>
@@ -52,6 +54,33 @@
                     </Menu.Styles>
                 </Menu>
             </StackPanel>
+        
+
+            <StackPanel>
+                <TextBlock Classes="h3" Margin="4 8">Mixed</TextBlock>
+                <Menu>
+                    <MenuItem Header="_File">
+                        <MenuItem Header="_New" CommandParameter="{Binding}" InputGesture="Ctrl+N"/>
+                        <Separator/>
+                        <MenuItem Header="_Open..." InputGesture="Ctrl+O"/>
+                        <Separator/>
+                        <MenuItem Header="Execu_te Script..." />
+                        <Separator/>
+                        <MenuItem Header="_Recent" Items="{Binding RecentItems}">
+                            <MenuItem.Styles>
+                                <Style Selector="MenuItem">
+                                    <Setter Property="Header" Value="{Binding Header}"/>
+                                </Style>
+                            </MenuItem.Styles>
+                        </MenuItem>
+                        <Separator/>
+                        <MenuItem Header="E_xit" InputGesture="Alt+F4"/>
+                    </MenuItem>
+                    <MenuItem Header="_Help">
+                        <MenuItem Header="_About"/>
+                    </MenuItem>
+                </Menu>
+            </StackPanel>
         </StackPanel>
     </StackPanel>
 </UserControl>
diff --git a/samples/ControlCatalog/ViewModels/MenuPageViewModel.cs b/samples/ControlCatalog/ViewModels/MenuPageViewModel.cs
index dc9c4a8f49..9e7ae8b716 100644
--- a/samples/ControlCatalog/ViewModels/MenuPageViewModel.cs
+++ b/samples/ControlCatalog/ViewModels/MenuPageViewModel.cs
@@ -17,6 +17,23 @@ namespace ControlCatalog.ViewModels
             SaveCommand = ReactiveCommand.Create(Save, Observable.Return(false));
             OpenRecentCommand = ReactiveCommand.Create<string>(OpenRecent);
 
+            var recentItems = new[]
+            {
+                new MenuItemViewModel
+                {
+                    Header = "File1.txt",
+                    Command = OpenRecentCommand,
+                    CommandParameter = @"c:\foo\File1.txt"
+                },
+                new MenuItemViewModel
+                {
+                    Header = "File2.txt",
+                    Command = OpenRecentCommand,
+                    CommandParameter = @"c:\foo\File2.txt"
+                },
+            };
+
+            RecentItems = recentItems;
             MenuItems = new[]
             {
                 new MenuItemViewModel
@@ -24,27 +41,13 @@ namespace ControlCatalog.ViewModels
                     Header = "_File",
                     Items = new[]
                     {
-                        new MenuItemViewModel { Header = "_Open...", Command = OpenCommand },
+                        new MenuItemViewModel { Header = "O_pen...", Command = OpenCommand },
                         new MenuItemViewModel { Header = "Save", Command = SaveCommand },
                         new MenuItemViewModel { Header = "-" },
                         new MenuItemViewModel
                         {
                             Header = "Recent",
-                            Items = new[]
-                            {
-                                new MenuItemViewModel
-                                {
-                                    Header = "File1.txt",
-                                    Command = OpenRecentCommand,
-                                    CommandParameter = @"c:\foo\File1.txt"
-                                },
-                                new MenuItemViewModel
-                                {
-                                    Header = "File2.txt",
-                                    Command = OpenRecentCommand,
-                                    CommandParameter = @"c:\foo\File2.txt"
-                                },
-                            }
+                            Items = recentItems
                         },
                     }
                 },
@@ -61,6 +64,7 @@ namespace ControlCatalog.ViewModels
         }
 
         public IReadOnlyList<MenuItemViewModel> MenuItems { get; set; }
+        public IReadOnlyList<MenuItemViewModel> RecentItems { get; set; }
         public ReactiveCommand<Unit, Unit> OpenCommand { get; }
         public ReactiveCommand<Unit, Unit> SaveCommand { get; }
         public ReactiveCommand<string, Unit> OpenRecentCommand { get; }
diff --git a/src/Avalonia.Animation/Avalonia.Animation.csproj b/src/Avalonia.Animation/Avalonia.Animation.csproj
index 73c619942e..ee91acf45e 100644
--- a/src/Avalonia.Animation/Avalonia.Animation.csproj
+++ b/src/Avalonia.Animation/Avalonia.Animation.csproj
@@ -1,9 +1,10 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>netstandard2.0</TargetFramework>    
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\Avalonia.Base\Avalonia.Base.csproj" />
   </ItemGroup>
   <Import Project="..\..\build\Rx.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Base/Avalonia.Base.csproj b/src/Avalonia.Base/Avalonia.Base.csproj
index cbcf7a7386..9bfd387ca9 100644
--- a/src/Avalonia.Base/Avalonia.Base.csproj
+++ b/src/Avalonia.Base/Avalonia.Base.csproj
@@ -3,7 +3,7 @@
     <TargetFramework>netstandard2.0</TargetFramework>
     <AssemblyName>Avalonia.Base</AssemblyName>
     <RootNamespace>Avalonia</RootNamespace>
-    <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
+    <AllowUnsafeBlocks>True</AllowUnsafeBlocks>    
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\Avalonia.Build.Tasks\Avalonia.Build.Tasks.csproj"/>
@@ -13,4 +13,5 @@
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\JetBrains.Annotations.props" />
   <Import Project="..\..\build\System.Memory.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Controls.DataGrid/Avalonia.Controls.DataGrid.csproj b/src/Avalonia.Controls.DataGrid/Avalonia.Controls.DataGrid.csproj
index 27853a1540..6975642db2 100644
--- a/src/Avalonia.Controls.DataGrid/Avalonia.Controls.DataGrid.csproj
+++ b/src/Avalonia.Controls.DataGrid/Avalonia.Controls.DataGrid.csproj
@@ -22,4 +22,5 @@
   <Import Project="..\..\build\EmbedXaml.props" />
   <Import Project="..\..\build\JetBrains.Annotations.props" />
   <Import Project="..\..\build\BuildTargets.targets" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Controls/Avalonia.Controls.csproj b/src/Avalonia.Controls/Avalonia.Controls.csproj
index 32331d29ab..480dcfcb85 100644
--- a/src/Avalonia.Controls/Avalonia.Controls.csproj
+++ b/src/Avalonia.Controls/Avalonia.Controls.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>netstandard2.0</TargetFramework>    
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\Avalonia.Animation\Avalonia.Animation.csproj" />
@@ -14,4 +14,5 @@
   </ItemGroup>
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\JetBrains.Annotations.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Controls/MenuItem.cs b/src/Avalonia.Controls/MenuItem.cs
index 912abc6de3..789e4f8926 100644
--- a/src/Avalonia.Controls/MenuItem.cs
+++ b/src/Avalonia.Controls/MenuItem.cs
@@ -97,7 +97,6 @@ namespace Avalonia.Controls
         private ICommand _command;
         private bool _commandCanExecute = true;
         private Popup _popup;
-        private IDisposable _gridHack;
 
         /// <summary>
         /// Initializes static members of the <see cref="MenuItem"/> class.
@@ -323,9 +322,6 @@ namespace Avalonia.Controls
             {
                 Command.CanExecuteChanged -= CanExecuteChanged;
             }
-
-            _gridHack?.Dispose();
-            _gridHack = null;
         }
 
         protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
@@ -345,9 +341,7 @@ namespace Avalonia.Controls
                 // the WPF codebase:
                 //
                 // https://github.com/dotnet/wpf/blob/89537909bdf36bc918e88b37751add46a8980bb0/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/MenuItem.cs#L2126-L2141
-                _gridHack = Bind(
-                    DefinitionBase.PrivateSharedSizeScopeProperty,
-                    parent.GetBindingObservable(DefinitionBase.PrivateSharedSizeScopeProperty));
+                SetValue(DefinitionBase.PrivateSharedSizeScopeProperty, parent.GetValue(DefinitionBase.PrivateSharedSizeScopeProperty));
             }
         }
 
diff --git a/src/Avalonia.DesignerSupport/Avalonia.DesignerSupport.csproj b/src/Avalonia.DesignerSupport/Avalonia.DesignerSupport.csproj
index 76ea8a3445..35bd0f97e1 100644
--- a/src/Avalonia.DesignerSupport/Avalonia.DesignerSupport.csproj
+++ b/src/Avalonia.DesignerSupport/Avalonia.DesignerSupport.csproj
@@ -9,6 +9,7 @@
     <Version>0.7.0</Version>
     <NoWarn>CS1591</NoWarn>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <NugetPackageName>Avalonia</NugetPackageName>
   </PropertyGroup>
   <ItemGroup>
     <EmbeddedResource Include="Remote\HtmlTransport\webapp\build\**\*.gz" />
@@ -26,4 +27,5 @@
     <ProjectReference Include="..\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
   </ItemGroup>
   <Import Project="..\..\build\Rx.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Desktop/Avalonia.Desktop.csproj b/src/Avalonia.Desktop/Avalonia.Desktop.csproj
index 72b7b5c1e7..a9589b7f2b 100644
--- a/src/Avalonia.Desktop/Avalonia.Desktop.csproj
+++ b/src/Avalonia.Desktop/Avalonia.Desktop.csproj
@@ -11,4 +11,6 @@
       <ProjectReference Include="../../packages/Avalonia/Avalonia.csproj" />
       <ProjectReference Include="../Avalonia.X11/Avalonia.X11.csproj" />
   </ItemGroup>
+  
+  <Import Project="..\..\build\ApiDiff.props" />  
 </Project>
diff --git a/src/Avalonia.DesktopRuntime/Avalonia.DesktopRuntime.csproj b/src/Avalonia.DesktopRuntime/Avalonia.DesktopRuntime.csproj
index c0e46416c1..805aae2d1a 100644
--- a/src/Avalonia.DesktopRuntime/Avalonia.DesktopRuntime.csproj
+++ b/src/Avalonia.DesktopRuntime/Avalonia.DesktopRuntime.csproj
@@ -17,4 +17,5 @@
   <Import Project="..\..\build\NetCore.props" />
   <Import Project="..\..\build\NetFX.props" />
   <Import Project="..\Shared\PlatformSupport\PlatformSupport.projitems" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj b/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj
index 5f49a46839..db8684747d 100644
--- a/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj
+++ b/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj
@@ -2,6 +2,7 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <RootNamespace>Avalonia</RootNamespace>
+    <PackageId>Avalonia.Diagnostics</PackageId>
   </PropertyGroup>
   <ItemGroup>
     <Compile Update="**\*.xaml.cs">
@@ -28,4 +29,5 @@
   <Import Project="..\..\build\EmbedXaml.props" />
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\BuildTargets.targets" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Dialogs/Avalonia.Dialogs.csproj b/src/Avalonia.Dialogs/Avalonia.Dialogs.csproj
index f54ddf32be..dd476e2559 100644
--- a/src/Avalonia.Dialogs/Avalonia.Dialogs.csproj
+++ b/src/Avalonia.Dialogs/Avalonia.Dialogs.csproj
@@ -15,4 +15,6 @@
   <ItemGroup>
     <ProjectReference Include="..\Markup\Avalonia.Markup.Xaml\Avalonia.Markup.Xaml.csproj" />
   </ItemGroup>
+
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.FreeDesktop/Avalonia.FreeDesktop.csproj b/src/Avalonia.FreeDesktop/Avalonia.FreeDesktop.csproj
index d9fd3b78a2..260d7350d2 100644
--- a/src/Avalonia.FreeDesktop/Avalonia.FreeDesktop.csproj
+++ b/src/Avalonia.FreeDesktop/Avalonia.FreeDesktop.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>netstandard2.0</TargetFramework>    
   </PropertyGroup>
 
   <ItemGroup>
@@ -10,6 +10,5 @@
 
   <ItemGroup>
     <PackageReference Include="Tmds.DBus" Version="0.7.0" />
-  </ItemGroup>
-
+  </ItemGroup>  
 </Project>
diff --git a/src/Avalonia.Headless/Avalonia.Headless.csproj b/src/Avalonia.Headless/Avalonia.Headless.csproj
index b871316a2c..ac591b68a8 100644
--- a/src/Avalonia.Headless/Avalonia.Headless.csproj
+++ b/src/Avalonia.Headless/Avalonia.Headless.csproj
@@ -1,8 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\packages\Avalonia\Avalonia.csproj" />
-  </ItemGroup>
+  </ItemGroup>  
 </Project>
diff --git a/src/Avalonia.Input/Avalonia.Input.csproj b/src/Avalonia.Input/Avalonia.Input.csproj
index ea560ce2ea..2204778afe 100644
--- a/src/Avalonia.Input/Avalonia.Input.csproj
+++ b/src/Avalonia.Input/Avalonia.Input.csproj
@@ -10,4 +10,5 @@
     <ProjectReference Include="..\Avalonia.Visuals\Avalonia.Visuals.csproj" />
   </ItemGroup>  
   <Import Project="..\..\build\Rx.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Interactivity/Avalonia.Interactivity.csproj b/src/Avalonia.Interactivity/Avalonia.Interactivity.csproj
index 730ca2bd6e..2da23410d6 100644
--- a/src/Avalonia.Interactivity/Avalonia.Interactivity.csproj
+++ b/src/Avalonia.Interactivity/Avalonia.Interactivity.csproj
@@ -11,4 +11,5 @@
     <ProjectReference Include="..\Avalonia.Visuals\Avalonia.Visuals.csproj" />
   </ItemGroup>
   <Import Project="..\..\build\Rx.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
\ No newline at end of file
diff --git a/src/Avalonia.Layout/Avalonia.Layout.csproj b/src/Avalonia.Layout/Avalonia.Layout.csproj
index 410a0791b1..076ec56cd6 100644
--- a/src/Avalonia.Layout/Avalonia.Layout.csproj
+++ b/src/Avalonia.Layout/Avalonia.Layout.csproj
@@ -8,4 +8,5 @@
     <ProjectReference Include="..\Avalonia.Visuals\Avalonia.Visuals.csproj" />
   </ItemGroup>  
   <Import Project="..\..\build\Rx.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Native/AvaloniaNativeMenuExporter.cs b/src/Avalonia.Native/AvaloniaNativeMenuExporter.cs
index 0f2551ffeb..41ad988c34 100644
--- a/src/Avalonia.Native/AvaloniaNativeMenuExporter.cs
+++ b/src/Avalonia.Native/AvaloniaNativeMenuExporter.cs
@@ -74,31 +74,34 @@ namespace Avalonia.Native
             return result;
         }
 
-        void DoLayoutReset()
+        private void DoLayoutReset()
         {
-            _resetQueued = false;
-
-            if (_nativeWindow is null)
+            if (_resetQueued)
             {
-                var appMenu = NativeMenu.GetMenu(Application.Current);
+                _resetQueued = false;
 
-                if (appMenu == null)
+                if (_nativeWindow is null)
                 {
-                    appMenu = CreateDefaultAppMenu();           
-                    NativeMenu.SetMenu(Application.Current, appMenu);         
-                }
+                    var appMenu = NativeMenu.GetMenu(Application.Current);
 
-                SetMenu(appMenu);
-            }
-            else
-            {
-                if (_menu != null)
+                    if (appMenu == null)
+                    {
+                        appMenu = CreateDefaultAppMenu();
+                        NativeMenu.SetMenu(Application.Current, appMenu);
+                    }
+
+                    SetMenu(appMenu);
+                }
+                else
                 {
-                    SetMenu(_nativeWindow, _menu);
+                    if (_menu != null)
+                    {
+                        SetMenu(_nativeWindow, _menu);
+                    }
                 }
-            }
 
-            _exported = true;
+                _exported = true;
+            }
         }
 
         internal void QueueReset()
diff --git a/src/Avalonia.OpenGL/Avalonia.OpenGL.csproj b/src/Avalonia.OpenGL/Avalonia.OpenGL.csproj
index 72132eed93..2e23f24deb 100644
--- a/src/Avalonia.OpenGL/Avalonia.OpenGL.csproj
+++ b/src/Avalonia.OpenGL/Avalonia.OpenGL.csproj
@@ -11,4 +11,5 @@
       <ProjectReference Include="..\Avalonia.Visuals\Avalonia.Visuals.csproj" />
     </ItemGroup>
 
+    <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.ReactiveUI/Avalonia.ReactiveUI.csproj b/src/Avalonia.ReactiveUI/Avalonia.ReactiveUI.csproj
index 64145b9c3c..d01a495108 100644
--- a/src/Avalonia.ReactiveUI/Avalonia.ReactiveUI.csproj
+++ b/src/Avalonia.ReactiveUI/Avalonia.ReactiveUI.csproj
@@ -8,4 +8,5 @@
   </ItemGroup>
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\ReactiveUI.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Remote.Protocol/Avalonia.Remote.Protocol.csproj b/src/Avalonia.Remote.Protocol/Avalonia.Remote.Protocol.csproj
index 6684772bfe..6c241bbc75 100644
--- a/src/Avalonia.Remote.Protocol/Avalonia.Remote.Protocol.csproj
+++ b/src/Avalonia.Remote.Protocol/Avalonia.Remote.Protocol.csproj
@@ -4,8 +4,10 @@
     <DefineConstants>AVALONIA_REMOTE_PROTOCOL;$(DefineConstants)</DefineConstants>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>Key.snk</AssemblyOriginatorKeyFile>
+    <PackageId>Avalonia.Remote.Protocol</PackageId>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="..\Avalonia.Input\Key.cs" />
   </ItemGroup>
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
\ No newline at end of file
diff --git a/src/Avalonia.Styling/Avalonia.Styling.csproj b/src/Avalonia.Styling/Avalonia.Styling.csproj
index b4f6c2c942..d9f0cef3da 100644
--- a/src/Avalonia.Styling/Avalonia.Styling.csproj
+++ b/src/Avalonia.Styling/Avalonia.Styling.csproj
@@ -8,4 +8,5 @@
     <ProjectReference Include="..\Avalonia.Animation\Avalonia.Animation.csproj" />
     <ProjectReference Include="..\Avalonia.Base\Avalonia.Base.csproj" />
   </ItemGroup>
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj b/src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj
index c44cc358e8..153e21761e 100644
--- a/src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj
+++ b/src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj
@@ -19,4 +19,5 @@
   </ItemGroup>
   <Import Project="..\..\build\BuildTargets.targets" />
   <Import Project="..\..\build\Rx.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Themes.Default/ComboBox.xaml b/src/Avalonia.Themes.Default/ComboBox.xaml
index ae5b902ae8..8ee818bad2 100644
--- a/src/Avalonia.Themes.Default/ComboBox.xaml
+++ b/src/Avalonia.Themes.Default/ComboBox.xaml
@@ -1,4 +1,5 @@
-<Styles xmlns="https://github.com/avaloniaui">
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Design.PreviewWith>
     <Border Padding="20">
       <StackPanel Spacing="10">
@@ -24,6 +25,7 @@
     <Setter Property="VerticalContentAlignment" Value="Center" />
     <Setter Property="Padding" Value="4" />
     <Setter Property="MinHeight" Value="20" />
+    <Setter Property="PlaceholderForeground" Value="{DynamicResource ComboBoxPlaceHolderForeground}" />
     <Setter Property="Template">
       <ControlTemplate>
         <Border Name="border"
@@ -31,6 +33,13 @@
                 BorderBrush="{TemplateBinding BorderBrush}"
                 BorderThickness="{TemplateBinding BorderThickness}">
           <Grid ColumnDefinitions="*,Auto">
+            <TextBlock Name="PlaceholderTextBlock"
+                       Grid.Column="0"
+                       HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
+                       VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+                       Margin="{TemplateBinding Padding}"
+                       Text="{TemplateBinding PlaceholderText}"
+                       IsVisible="{TemplateBinding SelectionBoxItem, Converter={x:Static ObjectConverters.IsNull}}" />
             <ContentControl Content="{TemplateBinding SelectionBoxItem}"
                             ContentTemplate="{TemplateBinding ItemTemplate}"
                             Margin="{TemplateBinding Padding}"
diff --git a/src/Avalonia.Themes.Default/DefaultTheme.xaml b/src/Avalonia.Themes.Default/DefaultTheme.xaml
index 97cff5d94b..4e63d1d223 100644
--- a/src/Avalonia.Themes.Default/DefaultTheme.xaml
+++ b/src/Avalonia.Themes.Default/DefaultTheme.xaml
@@ -37,6 +37,7 @@
   <StyleInclude Source="resm:Avalonia.Themes.Default.TextBox.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.ToggleButton.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.Expander.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.TitleBar.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.TreeView.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.TreeViewItem.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.UserControl.xaml?assembly=Avalonia.Themes.Default"/>
diff --git a/src/Avalonia.Themes.Default/TitleBar.xaml b/src/Avalonia.Themes.Default/TitleBar.xaml
index 45798d3fa1..4dba5b4ba4 100644
--- a/src/Avalonia.Themes.Default/TitleBar.xaml
+++ b/src/Avalonia.Themes.Default/TitleBar.xaml
@@ -15,7 +15,7 @@
           <Panel x:Name="PART_MouseTracker" Height="1" VerticalAlignment="Top" />
           <Panel x:Name="PART_Container">
             <Border x:Name="PART_Background" Background="{TemplateBinding Background}" />
-            <CaptionButtons x:Name="PART_CaptionButtons" VerticalAlignment="Top" HorizontalAlignment="Right" Foreground="{TemplateBinding Foreground}" MaxHeight="30" />
+            <CaptionButtons x:Name="PART_CaptionButtons" VerticalAlignment="Top" HorizontalAlignment="Right" Foreground="{TemplateBinding Foreground}" />
           </Panel>
         </Panel>
       </ControlTemplate>
diff --git a/src/Avalonia.Themes.Fluent/Avalonia.Themes.Fluent.csproj b/src/Avalonia.Themes.Fluent/Avalonia.Themes.Fluent.csproj
index c2a1359e8a..72f1fbf973 100644
--- a/src/Avalonia.Themes.Fluent/Avalonia.Themes.Fluent.csproj
+++ b/src/Avalonia.Themes.Fluent/Avalonia.Themes.Fluent.csproj
@@ -17,4 +17,5 @@
   </ItemGroup>
   <Import Project="..\..\build\BuildTargets.targets" />
   <Import Project="..\..\build\Rx.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Themes.Fluent/Button.xaml b/src/Avalonia.Themes.Fluent/Button.xaml
index 34bcd0f0c1..e58e8758d2 100644
--- a/src/Avalonia.Themes.Fluent/Button.xaml
+++ b/src/Avalonia.Themes.Fluent/Button.xaml
@@ -41,37 +41,37 @@
   </Style>
 
   <!-- PointerOverState -->  
-  <Style Selector="Button:pointerover /template/ ContentPresenter">
+  <Style Selector="Button:pointerover /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ButtonBackgroundPointerOver}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrushPointerOver}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ButtonForegroundPointerOver}" />
   </Style>
   
-  <Style Selector="Button:pressed  /template/ ContentPresenter">
+  <Style Selector="Button:pressed  /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ButtonBackgroundPressed}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrushPressed}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ButtonForegroundPressed}" />
   </Style>
   
-  <Style Selector="Button:disabled /template/ ContentPresenter">
+  <Style Selector="Button:disabled /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ButtonBackgroundDisabled}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrushDisabled}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ButtonForegroundDisabled}" />
   </Style>
 
-  <Style Selector="Button.accent /template/ ContentPresenter">
+  <Style Selector="Button.accent /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource AccentButtonBackground}" />
     <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrush}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource AccentButtonForeground}" />
   </Style>
 
-  <Style Selector="Button.accent:pointerover /template/ ContentPresenter">
+  <Style Selector="Button.accent:pointerover /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource AccentButtonBackgroundPointerOver}" />
     <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrushPointerOver}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource AccentButtonForegroundPointerOver}" />
   </Style>
 
-  <Style Selector="Button.accent:pressed  /template/ ContentPresenter">
+  <Style Selector="Button.accent:pressed  /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource AccentButtonBackgroundPressed}" />
     <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrushPressed}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource AccentButtonForegroundPressed}" />
@@ -90,7 +90,7 @@
     <Setter Property="RenderTransform" Value="scale(0.98)" />    
   </Style>
 
-  <Style Selector="Button.accent:disabled /template/ ContentPresenter">
+  <Style Selector="Button.accent:disabled /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource AccentButtonBackgroundDisabled}" />
     <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrushDisabled}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource AccentButtonForegroundDisabled}" />
diff --git a/src/Avalonia.Themes.Fluent/Menu.xaml b/src/Avalonia.Themes.Fluent/Menu.xaml
index 5f22f77d18..e62b76d293 100644
--- a/src/Avalonia.Themes.Fluent/Menu.xaml
+++ b/src/Avalonia.Themes.Fluent/Menu.xaml
@@ -11,10 +11,12 @@
   </Design.PreviewWith>
 
   <Style.Resources>
-    <x:Double x:Key="MenuHeight">32</x:Double>
+    <x:Double x:Key="MenuBarHeight">32</x:Double>
+    <Thickness x:Key="MenuBarItemPadding">12,0,12,0</Thickness>
   </Style.Resources>
+
   <Setter Property="Background" Value="Transparent" />
-  <Setter Property="Height" Value="{StaticResource MenuHeight}" />
+  <Setter Property="Height" Value="{StaticResource MenuBarHeight}" />
   <Setter Property="Template">
     <ControlTemplate>
       <Border Background="{TemplateBinding Background}"
diff --git a/src/Avalonia.Themes.Fluent/MenuItem.xaml b/src/Avalonia.Themes.Fluent/MenuItem.xaml
index fbb994e90c..5123ba4cf2 100644
--- a/src/Avalonia.Themes.Fluent/MenuItem.xaml
+++ b/src/Avalonia.Themes.Fluent/MenuItem.xaml
@@ -25,11 +25,12 @@
         </MenuItem>
         <MenuItem Header="Edit">
           <MenuItem Header="Go To">
-            <MenuItem Header="Go To Line"/>
+            <MenuItem Header="Go To Line" />
           </MenuItem>
         </MenuItem>
         <MenuItem Header="View">
-          <MenuItem Header="Designer" InputGesture="Shift+F7" />
+          <MenuItem Header="Designer"
+                    InputGesture="Shift+F7" />
         </MenuItem>
         <MenuItem Header="Project">
           <MenuItem Header="Add class" />
@@ -40,9 +41,10 @@
 
   <Styles.Resources>
     <conv:PlatformKeyGestureConverter x:Key="KeyGestureConverter" />
+    <x:Double x:Key="MenuFlyoutSubItemPopupHorizontalOffset">-4</x:Double>
     <Thickness x:Key="MenuFlyoutScrollerMargin">0,4,0,4</Thickness>
     <Thickness x:Key="MenuIconPresenterMargin">0,0,12,0</Thickness>
-    <Thickness x:Key="MenuInputGestureTextMargin">24,0,0,0</Thickness>    
+    <Thickness x:Key="MenuInputGestureTextMargin">24,0,0,0</Thickness>
     <StreamGeometry x:Key="MenuItemChevronPathData">M 1,0 10,10 l -9,10 -1,-1 L 8,10 -0,1 Z</StreamGeometry>
   </Styles.Resources>
 
@@ -54,83 +56,84 @@
     <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
     <Setter Property="Template">
       <ControlTemplate>
-        <Border Name="PART_LayoutRoot"
-                Padding="{TemplateBinding Padding}"
-                Background="{TemplateBinding Background}"
-                BorderBrush="{TemplateBinding BorderBrush}"
-                BorderThickness="{TemplateBinding BorderThickness}">
-          <Grid>
-            <Grid.ColumnDefinitions>
-              <ColumnDefinition Width="Auto"
-                                SharedSizeGroup="MenuItemIcon"  />
-              <ColumnDefinition Width="*" />
-              <ColumnDefinition Width="Auto"
-                                SharedSizeGroup="MenuItemIGT" />
-              <ColumnDefinition Width="Auto"
-                                SharedSizeGroup="MenuItemChevron" />
-            </Grid.ColumnDefinitions>
-            <ContentPresenter Name="PART_IconPresenter"
-                              Content="{TemplateBinding Icon}"
-                              Width="16"
-                              Height="16"
-                              Margin="{DynamicResource MenuIconPresenterMargin}"
-                              HorizontalAlignment="Center"
-                              VerticalAlignment="Center"/>
+        <Panel>
+          <Border Name="PART_LayoutRoot"
+                  Padding="{TemplateBinding Padding}"
+                  Background="{TemplateBinding Background}"
+                  BorderBrush="{TemplateBinding BorderBrush}"
+                  BorderThickness="{TemplateBinding BorderThickness}">
+            <Grid>
+              <Grid.ColumnDefinitions>
+                <ColumnDefinition Width="Auto"
+                                  SharedSizeGroup="MenuItemIcon" />
+                <ColumnDefinition Width="*" />
+                <ColumnDefinition Width="Auto"
+                                  SharedSizeGroup="MenuItemIGT" />
+                <ColumnDefinition Width="Auto"
+                                  SharedSizeGroup="MenuItemChevron" />
+              </Grid.ColumnDefinitions>
+              <ContentPresenter Name="PART_IconPresenter"
+                                Content="{TemplateBinding Icon}"
+                                Width="16"
+                                Height="16"
+                                Margin="{DynamicResource MenuIconPresenterMargin}"
+                                HorizontalAlignment="Center"
+                                VerticalAlignment="Center" />
 
-            <ContentPresenter Name="PART_HeaderPresenter"
-                              Content="{TemplateBinding Header}"
-                              VerticalAlignment="Center"
-                              HorizontalAlignment="Stretch"
-                              TextBlock.Foreground="{TemplateBinding Foreground}"
-                              Grid.Column="1">
-              <ContentPresenter.DataTemplates>
-                <DataTemplate DataType="sys:String">
-                  <AccessText Text="{Binding}" />
-                </DataTemplate>
-              </ContentPresenter.DataTemplates>
-            </ContentPresenter>
-            <TextBlock x:Name="PART_InputGestureText"
-                       Grid.Column="2"
-                       Classes="CaptionTextBlockStyle"
-                       Margin="{DynamicResource MenuInputGestureTextMargin}"
-                       Text="{TemplateBinding InputGesture,
-                                              Converter={StaticResource KeyGestureConverter}}"
-                       HorizontalAlignment="Right"
-                       VerticalAlignment="Center" />
-            <Path Name="PART_ChevronPath"
-                  Stretch="Uniform"
-                  Width="8"
-                  Height="16"
-                  Data="{StaticResource MenuItemChevronPathData}"
-                  Margin="{DynamicResource MenuFlyoutItemChevronMargin}"
-                  VerticalAlignment="Center"
-                  Grid.Column="3" />
-            <Popup Name="PART_Popup"
-                   WindowManagerAddShadowHint="True"
-                   PlacementMode="Right"
-                   StaysOpen="True"
-                   IsOpen="{TemplateBinding IsSubMenuOpen,
-                                            Mode=TwoWay}">
-              <Border Background="{DynamicResource MenuFlyoutPresenterBackground}"
-                      BorderBrush="{DynamicResource MenuFlyoutPresenterBorderBrush}"
-                      BorderThickness="{DynamicResource MenuFlyoutPresenterBorderThemeThickness}"
-                      Padding="{DynamicResource MenuFlyoutPresenterThemePadding}"
-                      MaxWidth="{DynamicResource FlyoutThemeMaxWidth}"
-                      MinHeight="{DynamicResource MenuFlyoutThemeMinHeight}"
-                      HorizontalAlignment="Stretch"
-                      CornerRadius="{DynamicResource OverlayCornerRadius}">
-                <ScrollViewer>
-                  <ItemsPresenter Name="PART_ItemsPresenter"
-                                  Items="{TemplateBinding Items}"
-                                  ItemsPanel="{TemplateBinding ItemsPanel}"
-                                  ItemTemplate="{TemplateBinding ItemTemplate}"
-                                  Margin="{DynamicResource MenuFlyoutScrollerMargin}"
-                                  Grid.IsSharedSizeScope="True" />
-                </ScrollViewer>
-              </Border>
-            </Popup>
-          </Grid>
-        </Border>
+              <ContentPresenter Name="PART_HeaderPresenter"
+                                Content="{TemplateBinding Header}"
+                                VerticalAlignment="Center"
+                                HorizontalAlignment="Stretch"
+                                TextBlock.Foreground="{TemplateBinding Foreground}"
+                                Grid.Column="1">
+                <ContentPresenter.DataTemplates>
+                  <DataTemplate DataType="sys:String">
+                    <AccessText Text="{Binding}" />
+                  </DataTemplate>
+                </ContentPresenter.DataTemplates>
+              </ContentPresenter>
+              <TextBlock x:Name="PART_InputGestureText"
+                         Grid.Column="2"
+                         Classes="CaptionTextBlockStyle"
+                         Margin="{DynamicResource MenuInputGestureTextMargin}"
+                         Text="{TemplateBinding InputGesture, Converter={StaticResource KeyGestureConverter}}"
+                         HorizontalAlignment="Right"
+                         VerticalAlignment="Center" />
+              <Path Name="PART_ChevronPath"
+                    Stretch="Uniform"
+                    Width="8"
+                    Height="16"
+                    Data="{StaticResource MenuItemChevronPathData}"
+                    Margin="{DynamicResource MenuFlyoutItemChevronMargin}"
+                    VerticalAlignment="Center"
+                    Grid.Column="3" />
+            </Grid>
+          </Border>
+          <Popup Name="PART_Popup"
+                 WindowManagerAddShadowHint="True"
+                 PlacementMode="Right"
+                 HorizontalOffset="{StaticResource MenuFlyoutSubItemPopupHorizontalOffset}"
+                 StaysOpen="True"
+                 IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
+            <Border Background="{DynamicResource MenuFlyoutPresenterBackground}"
+                    BorderBrush="{DynamicResource MenuFlyoutPresenterBorderBrush}"
+                    BorderThickness="{DynamicResource MenuFlyoutPresenterBorderThemeThickness}"
+                    Padding="{DynamicResource MenuFlyoutPresenterThemePadding}"
+                    MaxWidth="{DynamicResource FlyoutThemeMaxWidth}"
+                    MinHeight="{DynamicResource MenuFlyoutThemeMinHeight}"
+                    HorizontalAlignment="Stretch"
+                    CornerRadius="{DynamicResource OverlayCornerRadius}">
+              <ScrollViewer>
+                <ItemsPresenter Name="PART_ItemsPresenter"
+                                Items="{TemplateBinding Items}"
+                                ItemsPanel="{TemplateBinding ItemsPanel}"
+                                ItemTemplate="{TemplateBinding ItemTemplate}"
+                                Margin="{DynamicResource MenuFlyoutScrollerMargin}"
+                                Grid.IsSharedSizeScope="True" />
+              </ScrollViewer>
+            </Border>
+          </Popup>
+        </Panel>
       </ControlTemplate>
     </Setter>
   </Style>
@@ -145,6 +148,8 @@
           <Panel>
             <ContentPresenter Name="PART_HeaderPresenter"
                               Content="{TemplateBinding Header}"
+                              VerticalAlignment="Center"
+                              HorizontalAlignment="Stretch"
                               Margin="{TemplateBinding Padding}">
               <ContentPresenter.DataTemplates>
                 <DataTemplate DataType="sys:String">
@@ -155,8 +160,7 @@
             <Popup Name="PART_Popup"
                    WindowManagerAddShadowHint="False"
                    MinWidth="{Binding Bounds.Width, RelativeSource={RelativeSource TemplatedParent}}"
-                   IsOpen="{TemplateBinding IsSubMenuOpen,
-                                            Mode=TwoWay}"
+                   IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}"
                    StaysOpen="True">
               <Border Background="{DynamicResource MenuFlyoutPresenterBackground}"
                       BorderBrush="{DynamicResource MenuFlyoutPresenterBorderBrush}"
@@ -183,10 +187,15 @@
   </Style>
 
   <Style Selector="MenuItem">
-    <!-- Narrow padding should be used for mouse input, when non-narrow one should be used for touch input in future. -->
-    <Setter Property="Padding" Value="{DynamicResource MenuFlyoutItemThemePaddingNarrow}" />
+    <!--  Narrow padding should be used for mouse input, when non-narrow one should be used for touch input in future.  -->
+    <Setter Property="Padding" Value="{StaticResource MenuFlyoutItemThemePaddingNarrow}" />
   </Style>
-  
+
+  <Style Selector="Menu > MenuItem">
+    <!--  Custom padding for Menu > MenuItem  -->
+    <Setter Property="Padding" Value="{StaticResource MenuBarItemPadding}" />
+  </Style>
+
   <Style Selector="MenuItem /template/ ContentPresenter#PART_IconPresenter">
     <Setter Property="IsVisible" Value="False" />
   </Style>
@@ -212,14 +221,15 @@
     <Setter Property="Fill" Value="{DynamicResource MenuFlyoutSubItemChevronPointerOver}" />
   </Style>
 
-  <Style Selector="MenuItem:pressed /template/ Border#PART_LayoutRoot">
+  <!--  Listen for PART_LayoutRoot:pointerover, so it will not be triggered when subitem is pressed  -->
+  <Style Selector="MenuItem:pressed /template/ Border#PART_LayoutRoot:pointerover">
     <Setter Property="Background" Value="{DynamicResource MenuFlyoutItemBackgroundPressed}" />
     <Setter Property="BorderBrush" Value="{DynamicResource MenuFlyoutItemBorderBrushPressed}" />
   </Style>
-  <Style Selector="MenuItem:pressed /template/ TextBlock#PART_InputGestureText">
+  <Style Selector="MenuItem:pressed /template/ Border#PART_LayoutRoot:pointerover TextBlock#PART_InputGestureText">
     <Setter Property="Foreground" Value="{DynamicResource MenuFlyoutItemKeyboardAcceleratorTextForegroundPressed}" />
   </Style>
-  <Style Selector="MenuItem:pressed /template/ Path#PART_ChevronPath">
+  <Style Selector="MenuItem:pressed /template/ Border#PART_LayoutRoot:pointerover Path#PART_ChevronPath">
     <Setter Property="Fill" Value="{DynamicResource MenuFlyoutSubItemChevronPressed}" />
   </Style>
 
diff --git a/src/Avalonia.Themes.Fluent/RepeatButton.xaml b/src/Avalonia.Themes.Fluent/RepeatButton.xaml
index 5afaf05e9f..70a6b8a2ee 100644
--- a/src/Avalonia.Themes.Fluent/RepeatButton.xaml
+++ b/src/Avalonia.Themes.Fluent/RepeatButton.xaml
@@ -37,23 +37,23 @@
     </Setter>
   </Style>
 
-  <Style Selector="RepeatButton /template/ ContentPresenter">
+  <Style Selector="RepeatButton /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
   </Style>
 
-  <Style Selector="RepeatButton:pointerover /template/ ContentPresenter">
+  <Style Selector="RepeatButton:pointerover /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource RepeatButtonBackgroundPointerOver}" />
     <Setter Property="BorderBrush" Value="{DynamicResource RepeatButtonBorderBrushPointerOver}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource RepeatButtonForegroundPointerOver}" />
   </Style>
 
-  <Style Selector="RepeatButton:pressed  /template/ ContentPresenter">
+  <Style Selector="RepeatButton:pressed  /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource RepeatButtonBackgroundPressed}" />
     <Setter Property="BorderBrush" Value="{DynamicResource RepeatButtonBorderBrushPressed}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource RepeatButtonForegroundPressed}" />
   </Style>
 
-  <Style Selector="RepeatButton:disabled /template/ ContentPresenter">
+  <Style Selector="RepeatButton:disabled /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource RepeatButtonBackgroundDisabled}" />
     <Setter Property="BorderBrush" Value="{DynamicResource RepeatButtonBorderBrushDisabled}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource RepeatButtonForegroundDisabled}" />
diff --git a/src/Avalonia.Themes.Fluent/TitleBar.xaml b/src/Avalonia.Themes.Fluent/TitleBar.xaml
index 45798d3fa1..4dba5b4ba4 100644
--- a/src/Avalonia.Themes.Fluent/TitleBar.xaml
+++ b/src/Avalonia.Themes.Fluent/TitleBar.xaml
@@ -15,7 +15,7 @@
           <Panel x:Name="PART_MouseTracker" Height="1" VerticalAlignment="Top" />
           <Panel x:Name="PART_Container">
             <Border x:Name="PART_Background" Background="{TemplateBinding Background}" />
-            <CaptionButtons x:Name="PART_CaptionButtons" VerticalAlignment="Top" HorizontalAlignment="Right" Foreground="{TemplateBinding Foreground}" MaxHeight="30" />
+            <CaptionButtons x:Name="PART_CaptionButtons" VerticalAlignment="Top" HorizontalAlignment="Right" Foreground="{TemplateBinding Foreground}" />
           </Panel>
         </Panel>
       </ControlTemplate>
diff --git a/src/Avalonia.Themes.Fluent/ToggleButton.xaml b/src/Avalonia.Themes.Fluent/ToggleButton.xaml
index f2f07d3e2a..49e2280a6d 100644
--- a/src/Avalonia.Themes.Fluent/ToggleButton.xaml
+++ b/src/Avalonia.Themes.Fluent/ToggleButton.xaml
@@ -39,67 +39,67 @@
     </Setter>
   </Style>
 
-  <Style Selector="ToggleButton:pointerover /template/ ContentPresenter">
+  <Style Selector="ToggleButton:pointerover /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundPointerOver}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushPointerOver}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundPointerOver}" />
   </Style>
 
-  <Style Selector="ToggleButton:pressed  /template/ ContentPresenter">
+  <Style Selector="ToggleButton:pressed  /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundPressed}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushPressed}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundPressed}" />
   </Style>
 
-  <Style Selector="ToggleButton:disabled /template/ ContentPresenter">
+  <Style Selector="ToggleButton:disabled /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundDisabled}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushDisabled}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundDisabled}" />
   </Style>
 
-  <Style Selector="ToggleButton:checked /template/ ContentPresenter">
+  <Style Selector="ToggleButton:checked /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundChecked}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushChecked}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundChecked}" />
   </Style>
 
-  <Style Selector="ToggleButton:checked:pointerover /template/ ContentPresenter">
+  <Style Selector="ToggleButton:checked:pointerover /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedPointerOver}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedPointerOver}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedPointerOver}" />
   </Style>
 
-  <Style Selector="ToggleButton:checked:pressed /template/ ContentPresenter">
+  <Style Selector="ToggleButton:checked:pressed /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedPressed}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedPressed}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedPressed}" />
   </Style>
 
-  <Style Selector="ToggleButton:checked:disabled /template/ ContentPresenter">
+  <Style Selector="ToggleButton:checked:disabled /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedDisabled}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedDisabled}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedDisabled}" />
   </Style>
 
-  <Style Selector="ToggleButton:indeterminate /template/ ContentPresenter">
+  <Style Selector="ToggleButton:indeterminate /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminate}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminate}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminate}" />
   </Style>
 
-  <Style Selector="ToggleButton:indeterminate:pointerover /template/ ContentPresenter">
+  <Style Selector="ToggleButton:indeterminate:pointerover /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminatePointerOver}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminatePointerOver}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminatePointerOver}" />
   </Style>
 
-  <Style Selector="ToggleButton:indeterminate:pressed /template/ ContentPresenter">
+  <Style Selector="ToggleButton:indeterminate:pressed /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminatePressed}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminatePressed}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminatePressed}" />
   </Style>
 
-  <Style Selector="ToggleButton:indeterminate:disabled /template/ ContentPresenter">
+  <Style Selector="ToggleButton:indeterminate:disabled /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminateDisabled}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminateDisabled}" />
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminateDisabled}" />
diff --git a/src/Avalonia.Visuals/Avalonia.Visuals.csproj b/src/Avalonia.Visuals/Avalonia.Visuals.csproj
index 576200a996..802a120e03 100644
--- a/src/Avalonia.Visuals/Avalonia.Visuals.csproj
+++ b/src/Avalonia.Visuals/Avalonia.Visuals.csproj
@@ -14,4 +14,5 @@
   </ItemGroup>
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\System.Memory.props" />
+  <Import Project="..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Avalonia.Visuals/Media/CharacterHit.cs b/src/Avalonia.Visuals/Media/CharacterHit.cs
index ba691dad6e..f018b2d8a9 100644
--- a/src/Avalonia.Visuals/Media/CharacterHit.cs
+++ b/src/Avalonia.Visuals/Media/CharacterHit.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics;
 
 namespace Avalonia.Media
 {
@@ -9,6 +10,7 @@ namespace Avalonia.Media
     ///     The CharacterHit structure provides information about the index of the first
     ///     character that got hit as well as information about leading or trailing edge.
     /// </remarks>
+    [DebuggerDisplay("CharacterHit({FirstCharacterIndex}, {TrailingLength})")]
     public readonly struct CharacterHit : IEquatable<CharacterHit>
     {
         /// <summary>
diff --git a/src/Avalonia.Visuals/Media/TextFormatting/TextLineImpl.cs b/src/Avalonia.Visuals/Media/TextFormatting/TextLineImpl.cs
index f73a7be759..435752160e 100644
--- a/src/Avalonia.Visuals/Media/TextFormatting/TextLineImpl.cs
+++ b/src/Avalonia.Visuals/Media/TextFormatting/TextLineImpl.cs
@@ -236,7 +236,7 @@ namespace Avalonia.Media.TextFormatting
 
             var codepointIndex = characterHit.FirstCharacterIndex + characterHit.TrailingLength;
 
-            if (codepointIndex >= TextRange.Start + TextRange.Length)
+            if (codepointIndex > TextRange.End)
             {
                 return false; // Cannot go forward anymore
             }
@@ -249,11 +249,14 @@ namespace Avalonia.Media.TextFormatting
 
                 var foundCharacterHit = run.GlyphRun.FindNearestCharacterHit(characterHit.FirstCharacterIndex + characterHit.TrailingLength, out _);
 
-                nextCharacterHit = characterHit.TrailingLength != 0 ?
+                var isAtEnd = foundCharacterHit.FirstCharacterIndex + foundCharacterHit.TrailingLength ==
+                              TextRange.Length;
+
+                nextCharacterHit = isAtEnd || characterHit.TrailingLength != 0 ?
                     foundCharacterHit :
                     new CharacterHit(foundCharacterHit.FirstCharacterIndex + foundCharacterHit.TrailingLength);
 
-                if (nextCharacterHit.FirstCharacterIndex > characterHit.FirstCharacterIndex)
+                if (isAtEnd || nextCharacterHit.FirstCharacterIndex > characterHit.FirstCharacterIndex)
                 {
                     return true;
                 }
@@ -272,6 +275,13 @@ namespace Avalonia.Media.TextFormatting
         /// <returns></returns>
         private bool TryFindPreviousCharacterHit(CharacterHit characterHit, out CharacterHit previousCharacterHit)
         {
+            if (characterHit.FirstCharacterIndex == TextRange.Start)
+            {
+                previousCharacterHit = new CharacterHit(TextRange.Start);
+
+                return true;
+            }
+
             previousCharacterHit = characterHit;
 
             var codepointIndex = characterHit.FirstCharacterIndex + characterHit.TrailingLength;
@@ -354,7 +364,7 @@ namespace Avalonia.Media.TextFormatting
 
             return new ShapedTextCharacters(glyphRun, textRun.Properties);
         }
-        
+
         /// <summary>
         /// Gets the shaped width of specified shaped text characters.
         /// </summary>
diff --git a/src/Avalonia.X11/NativeDialogs/Gtk.cs b/src/Avalonia.X11/NativeDialogs/Gtk.cs
index 82cf3c934f..77e410162f 100644
--- a/src/Avalonia.X11/NativeDialogs/Gtk.cs
+++ b/src/Avalonia.X11/NativeDialogs/Gtk.cs
@@ -204,6 +204,9 @@ namespace Avalonia.X11.NativeDialogs
         
         [DllImport(GtkName)]
         public static extern IntPtr gtk_file_chooser_add_filter(IntPtr chooser, IntPtr filter);
+
+        [DllImport(GtkName)]
+        public static extern IntPtr gtk_file_chooser_get_filter(IntPtr chooser);
         
         [DllImport(GtkName)]
         public static extern void gtk_widget_realize(IntPtr gtkWidget);
diff --git a/src/Avalonia.X11/NativeDialogs/GtkNativeFileDialogs.cs b/src/Avalonia.X11/NativeDialogs/GtkNativeFileDialogs.cs
index 287a541bc8..6cf6c6f35f 100644
--- a/src/Avalonia.X11/NativeDialogs/GtkNativeFileDialogs.cs
+++ b/src/Avalonia.X11/NativeDialogs/GtkNativeFileDialogs.cs
@@ -16,7 +16,7 @@ namespace Avalonia.X11.NativeDialogs
     {
         private Task<bool> _initialized;
         private unsafe  Task<string[]> ShowDialog(string title, IWindowImpl parent, GtkFileChooserAction action,
-            bool multiSelect, string initialFileName, IEnumerable<FileDialogFilter> filters)
+            bool multiSelect, string initialFileName, IEnumerable<FileDialogFilter> filters, string defaultExtension)
         {
             IntPtr dlg;
             using (var name = new Utf8Buffer(title))
@@ -35,11 +35,13 @@ namespace Avalonia.X11.NativeDialogs
                 foreach (var d in disposables) d.Dispose();
                 disposables.Clear();
             }
-            
+
+            var filtersDic = new Dictionary<IntPtr, FileDialogFilter>();
             if(filters != null)
                 foreach (var f in filters)
                 {
                     var filter = gtk_file_filter_new();
+                    filtersDic[filter] = f;
                     using (var b = new Utf8Buffer(f.Name))
                         gtk_file_filter_set_name(filter, b);
                     
@@ -74,6 +76,15 @@ namespace Avalonia.X11.NativeDialogs
                         }
                         g_slist_free(gs);
                         result = resultList.ToArray();
+                        
+                        // GTK doesn't auto-append the extension, so we need to do that manually
+                        if (action == GtkFileChooserAction.Save)
+                        {
+                            var currentFilter = gtk_file_chooser_get_filter(dlg);
+                            filtersDic.TryGetValue(currentFilter, out var selectedFilter);
+                            for (var c = 0; c < result.Length; c++)
+                                result[c] = NameWithExtension(result[c], defaultExtension, selectedFilter);
+                        }
                     }
 
                     gtk_widget_hide(dlg);
@@ -101,7 +112,30 @@ namespace Avalonia.X11.NativeDialogs
             gtk_window_present(dlg);
             return tcs.Task;
         }
-        
+
+        string NameWithExtension(string path, string defaultExtension, FileDialogFilter filter)
+        {
+            var name = Path.GetFileName(path);
+            if (name != null && !name.Contains("."))
+            {
+                if (filter?.Extensions?.Count > 0)
+                {
+                    if (defaultExtension != null
+                        && filter.Extensions.Contains(defaultExtension))
+                        return path + "." + defaultExtension.TrimStart('.');
+
+                    var ext = filter.Extensions.FirstOrDefault(x => x != "*");
+                    if (ext != null)
+                        return path + "." + ext.TrimStart('.');
+                }
+
+                if (defaultExtension != null)
+                    path += "." + defaultExtension.TrimStart('.');
+            }
+
+            return path;
+        }
+
         public async Task<string[]> ShowFileDialogAsync(FileDialog dialog, Window parent)
         {
             await EnsureInitialized();
@@ -113,7 +147,8 @@ namespace Avalonia.X11.NativeDialogs
                     dialog is OpenFileDialog ? GtkFileChooserAction.Open : GtkFileChooserAction.Save,
                     (dialog as OpenFileDialog)?.AllowMultiple ?? false,
                     Path.Combine(string.IsNullOrEmpty(dialog.Directory) ? "" : dialog.Directory,
-                        string.IsNullOrEmpty(dialog.InitialFileName) ? "" : dialog.InitialFileName), dialog.Filters));
+                        string.IsNullOrEmpty(dialog.InitialFileName) ? "" : dialog.InitialFileName), dialog.Filters,
+                    (dialog as SaveFileDialog)?.DefaultExtension));
         }
 
         public async Task<string> ShowFolderDialogAsync(OpenFolderDialog dialog, Window parent)
@@ -125,7 +160,7 @@ namespace Avalonia.X11.NativeDialogs
             return await await RunOnGlibThread(async () =>
             {
                 var res = await ShowDialog(dialog.Title, platformImpl,
-                    GtkFileChooserAction.SelectFolder, false, dialog.Directory, null);
+                    GtkFileChooserAction.SelectFolder, false, dialog.Directory, null, null);
                 return res?.FirstOrDefault();
             });
         }
diff --git a/src/Linux/Avalonia.LinuxFramebuffer/Avalonia.LinuxFramebuffer.csproj b/src/Linux/Avalonia.LinuxFramebuffer/Avalonia.LinuxFramebuffer.csproj
index 48095a4c25..22599200bc 100644
--- a/src/Linux/Avalonia.LinuxFramebuffer/Avalonia.LinuxFramebuffer.csproj
+++ b/src/Linux/Avalonia.LinuxFramebuffer/Avalonia.LinuxFramebuffer.csproj
@@ -7,5 +7,6 @@
   <ItemGroup>
     <ProjectReference Include="..\..\..\packages\Avalonia\Avalonia.csproj" />
     <ProjectReference Include="..\..\Skia\Avalonia.Skia\Avalonia.Skia.csproj" />
-  </ItemGroup>  
+  </ItemGroup>
+  <Import Project="..\..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Markup/Avalonia.Markup.Xaml.Loader/Avalonia.Markup.Xaml.Loader.csproj b/src/Markup/Avalonia.Markup.Xaml.Loader/Avalonia.Markup.Xaml.Loader.csproj
index 768545eb7e..514556d0b9 100644
--- a/src/Markup/Avalonia.Markup.Xaml.Loader/Avalonia.Markup.Xaml.Loader.csproj
+++ b/src/Markup/Avalonia.Markup.Xaml.Loader/Avalonia.Markup.Xaml.Loader.csproj
@@ -3,6 +3,7 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <IsPackable>true</IsPackable>
+    <PackageId>Avalonia.Markup.Xaml.Loader</PackageId>
   </PropertyGroup>
   <Import Project="IncludeXamlIlSre.props" />
   <ItemGroup>
@@ -10,5 +11,5 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Avalonia.Markup.Xaml\Avalonia.Markup.Xaml.csproj" />
-  </ItemGroup>
+  </ItemGroup>  
 </Project>
diff --git a/src/Markup/Avalonia.Markup.Xaml.Loader/xamlil.github b/src/Markup/Avalonia.Markup.Xaml.Loader/xamlil.github
index 7b8b3013bd..8d9fee734a 160000
--- a/src/Markup/Avalonia.Markup.Xaml.Loader/xamlil.github
+++ b/src/Markup/Avalonia.Markup.Xaml.Loader/xamlil.github
@@ -1 +1 @@
-Subproject commit 7b8b3013bd42e1992838a525c991f44191da55be
+Subproject commit 8d9fee734afaced9366774fda41b6aa2ab19875f
diff --git a/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj b/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
index 24428253aa..44a082e2df 100644
--- a/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
+++ b/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
@@ -64,4 +64,5 @@
     <ProjectReference Include="..\Avalonia.Markup\Avalonia.Markup.csproj" />
   </ItemGroup>
   <Import Project="..\..\..\build\Rx.props" />
+  <Import Project="..\..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj b/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj
index aca39dd8b0..89e2c096ee 100644
--- a/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj
+++ b/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj
@@ -16,4 +16,5 @@
   </ItemGroup>
   <Import Project="..\..\..\build\Rx.props" />
   <Import Project="..\..\..\build\System.Memory.props" />
+  <Import Project="..\..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Skia/Avalonia.Skia/Avalonia.Skia.csproj b/src/Skia/Avalonia.Skia/Avalonia.Skia.csproj
index d5ad70b944..ef955eb8be 100644
--- a/src/Skia/Avalonia.Skia/Avalonia.Skia.csproj
+++ b/src/Skia/Avalonia.Skia/Avalonia.Skia.csproj
@@ -17,4 +17,5 @@
   <Import Project="..\..\..\build\SkiaSharp.props" />
   <Import Project="..\..\..\build\HarfBuzzSharp.props" />
   <Import Project="..\..\Shared\RenderHelpers\RenderHelpers.projitems" Label="Shared" />
+  <Import Project="..\..\..\build\ApiDiff.props" />
 </Project>
diff --git a/src/Windows/Avalonia.Win32/Avalonia.Win32.csproj b/src/Windows/Avalonia.Win32/Avalonia.Win32.csproj
index 49700710e9..bcbdde322c 100644
--- a/src/Windows/Avalonia.Win32/Avalonia.Win32.csproj
+++ b/src/Windows/Avalonia.Win32/Avalonia.Win32.csproj
@@ -9,4 +9,5 @@
     <PackageReference Include="Avalonia.Angle.Windows.Natives" Version="2.1.0.2019013001" />
   </ItemGroup>
   <Import Project="$(MSBuildThisFileDirectory)\..\..\..\build\System.Drawing.Common.props" />  
+  <Import Project="..\..\..\build\ApiDiff.props" />
 </Project>
diff --git a/tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextLineTests.cs b/tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextLineTests.cs
index 09cbf3bf08..3655d78c9d 100644
--- a/tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextLineTests.cs
+++ b/tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextLineTests.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using Avalonia.Media;
 using Avalonia.Media.TextFormatting;
@@ -101,7 +102,7 @@ namespace Avalonia.Skia.UnitTests.Media.TextFormatting
 
                 Assert.Equal(firstCharacterHit.FirstCharacterIndex, previousCharacterHit.FirstCharacterIndex);
 
-                Assert.Equal(firstCharacterHit.TrailingLength, previousCharacterHit.TrailingLength);
+                Assert.Equal(0, previousCharacterHit.TrailingLength);
 
                 previousCharacterHit = new CharacterHit(clusters[^1], text.Length - clusters[^1]);
 
@@ -119,7 +120,7 @@ namespace Avalonia.Skia.UnitTests.Media.TextFormatting
 
                 Assert.Equal(firstCharacterHit.FirstCharacterIndex, previousCharacterHit.FirstCharacterIndex);
 
-                Assert.Equal(firstCharacterHit.TrailingLength, previousCharacterHit.TrailingLength);
+                Assert.Equal(0, previousCharacterHit.TrailingLength);
             }
         }