Merge branch 'master' into fixes/inlinesTrimming

native/Avalonia.Native/src/OSX/Avalonia.Native.OSX.xcodeproj/project.pbxproj

@@ -59,6 +59,7 @@
 		BC11A5BE2608D58F0017BAD0 /* automation.h in Headers */ = {isa = PBXBuildFile; fileRef = BC11A5BC2608D58F0017BAD0 /* automation.h */; };
 		BC11A5BF2608D58F0017BAD0 /* automation.mm in Sources */ = {isa = PBXBuildFile; fileRef = BC11A5BD2608D58F0017BAD0 /* automation.mm */; };
 		ED3791C42862E1F40080BD62 /* UniformTypeIdentifiers.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = ED3791C32862E1F40080BD62 /* UniformTypeIdentifiers.framework */; };
+		ED754D262A97306B0078B4DF /* PlatformRenderTimer.mm in Sources */ = {isa = PBXBuildFile; fileRef = ED754D252A97306B0078B4DF /* PlatformRenderTimer.mm */; };
 		EDF8CDCD2964CB01001EE34F /* PlatformSettings.mm in Sources */ = {isa = PBXBuildFile; fileRef = EDF8CDCC2964CB01001EE34F /* PlatformSettings.mm */; };
 /* End PBXBuildFile section */
 
@@ -122,6 +123,7 @@
 		BC11A5BC2608D58F0017BAD0 /* automation.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = automation.h; sourceTree = "<group>"; };
 		BC11A5BD2608D58F0017BAD0 /* automation.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = automation.mm; sourceTree = "<group>"; };
 		ED3791C32862E1F40080BD62 /* UniformTypeIdentifiers.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = UniformTypeIdentifiers.framework; path = System/Library/Frameworks/UniformTypeIdentifiers.framework; sourceTree = SDKROOT; };
+		ED754D252A97306B0078B4DF /* PlatformRenderTimer.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = PlatformRenderTimer.mm; sourceTree = "<group>"; };
 		EDF8CDCC2964CB01001EE34F /* PlatformSettings.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = PlatformSettings.mm; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -162,6 +164,7 @@
 		AB7A61E62147C814003C5833 = {
 			isa = PBXGroup;
 			children = (
+				ED754D252A97306B0078B4DF /* PlatformRenderTimer.mm */,
 				855EDC9E28C6546F00807998 /* PlatformBehaviorInhibition.mm */,
 				8D2F3511292F6AAE007FCF54 /* AvnTextInputMethodDelegate.h */,
 				8D300D68292E1E5D00320C49 /* AvnTextInputMethod.mm */,
@@ -333,6 +336,7 @@
 				18391068E48EF96E3DB5FDAB /* ResizeScope.mm in Sources */,
 				18391D4EB311BC7EF8B8C0A6 /* AvnView.mm in Sources */,
 				18391AA7E0BBA74D184C5734 /* AutoFitContentView.mm in Sources */,
+				ED754D262A97306B0078B4DF /* PlatformRenderTimer.mm in Sources */,
 				1839151F32D1BB1AB51A7BB6 /* AvnPanelWindow.mm in Sources */,
 				18391AC16726CBC45856233B /* AvnWindow.mm in Sources */,
 				18391D8CD1756DC858DC1A09 /* PopupImpl.mm in Sources */,

native/Avalonia.Native/src/OSX/PlatformRenderTimer.mm

@@ -0,0 +1,84 @@
+#include "common.h"
+
+class PlatformRenderTimer : public ComSingleObject<IAvnPlatformRenderTimer, &IID_IAvnPlatformRenderTimer>
+{
+private:
+    ComPtr<IAvnActionCallback> _callback;
+    CVDisplayLinkRef _displayLink;
+
+public:
+    FORWARD_IUNKNOWN()
+    virtual HRESULT RegisterTick (
+        IAvnActionCallback* callback) override
+    {
+        START_COM_CALL;
+        
+        @autoreleasepool
+        {
+            if (_displayLink != nil)
+            {
+                return E_UNEXPECTED;
+            }
+
+            _callback = callback;
+            auto result = CVDisplayLinkCreateWithActiveCGDisplays(&_displayLink);
+            if (result != 0)
+            {
+                return E_FAIL;
+            }
+
+            result = CVDisplayLinkSetOutputCallback(_displayLink, OnTick, this);
+            if (result != 0)
+            {
+                return E_FAIL;
+            }
+        }
+        return S_OK;
+    }
+
+    virtual void Start () override
+    {
+        START_COM_CALL;
+
+        @autoreleasepool
+        {
+            if (CVDisplayLinkIsRunning(_displayLink) == false) {
+                CVDisplayLinkStart(_displayLink);
+            }
+        }
+    }
+
+    virtual void Stop () override
+    {
+        START_COM_CALL;
+
+        @autoreleasepool
+        {
+            if (CVDisplayLinkIsRunning(_displayLink) == true) {
+                CVDisplayLinkStop(_displayLink);
+            }
+        }
+    }
+
+    virtual bool RunsInBackground () override
+    {
+        START_COM_CALL;
+
+        @autoreleasepool
+        {
+            return true;
+        }
+    }
+    
+    static CVReturn OnTick(CVDisplayLinkRef displayLink, const CVTimeStamp *inNow, const CVTimeStamp *inOutputTime, CVOptionFlags flagsIn, CVOptionFlags *flagsOut, void *displayLinkContext)
+    {
+        PlatformRenderTimer *object = (PlatformRenderTimer *)displayLinkContext;
+        object->_callback->Run();
+        return kCVReturnSuccess;
+    }
+};
+
+extern IAvnPlatformRenderTimer* CreatePlatformRenderTimer()
+{
+    return new PlatformRenderTimer();
+}

native/Avalonia.Native/src/OSX/common.h

@@ -32,6 +32,7 @@ extern IAvnApplicationCommands* CreateApplicationCommands();
 extern IAvnPlatformBehaviorInhibition* CreatePlatformBehaviorInhibition();
 extern IAvnNativeControlHost* CreateNativeControlHost(NSView* parent);
 extern IAvnPlatformSettings* CreatePlatformSettings();
+extern IAvnPlatformRenderTimer* CreatePlatformRenderTimer();
 extern void SetAppMenu(IAvnMenu *menu);
 extern void SetServicesMenu (IAvnMenu* menu);
 extern IAvnMenu* GetAppMenu ();

native/Avalonia.Native/src/OSX/main.mm

@@ -446,6 +446,17 @@ public:
             return S_OK;
         }
     }
+    
+    virtual HRESULT CreatePlatformRenderTimer(IAvnPlatformRenderTimer** ppv) override
+    {
+        START_COM_CALL;
+        
+        @autoreleasepool
+        {
+            *ppv = ::CreatePlatformRenderTimer();
+            return S_OK;
+        }
+    }
 };
 
 extern "C" IAvaloniaNativeFactory* CreateAvaloniaNative()

src/Avalonia.Base/Media/TextFormatting/TextLineImpl.cs

@@ -1278,14 +1278,11 @@ namespace Avalonia.Media.TextFormatting
             var start = GetParagraphOffsetX(width, widthIncludingWhitespace);
             var overhangLeading = Math.Max(0, bounds.Left - start);
             var overhangTrailing = Math.Max(0, bounds.Width - widthIncludingWhitespace);
-            var hasOverflowed = overhangLeading + widthIncludingWhitespace + overhangTrailing > _paragraphWidth;
+            var hasOverflowed = width > _paragraphWidth;
 
             if (!double.IsNaN(lineHeight) && !MathUtilities.IsZero(lineHeight))
             {
-                if (lineHeight > height)
-                {
-                    height = lineHeight;
-                }
+                height = lineHeight;
             }
 
             return new TextLineMetrics

src/Avalonia.Controls/Documents/Inline.cs

@@ -10,12 +10,14 @@ namespace Avalonia.Controls.Documents
     /// </summary>
     public abstract class Inline : TextElement
     {
+        // TODO12: change the field type to an AttachedProperty for consistency (breaking change)
         /// <summary>
         /// AvaloniaProperty for <see cref="TextDecorations" /> property.
         /// </summary>
         public static readonly StyledProperty<TextDecorationCollection?> TextDecorationsProperty =
-            AvaloniaProperty.Register<Inline, TextDecorationCollection?>(
-                nameof(TextDecorations));
+            AvaloniaProperty.RegisterAttached<Inline, Inline, TextDecorationCollection?>(
+                nameof(TextDecorations),
+                inherits: true);
 
         /// <summary>
         /// AvaloniaProperty for <see cref="BaselineAlignment" /> property.
@@ -43,7 +45,27 @@ namespace Avalonia.Controls.Documents
             get { return GetValue(BaselineAlignmentProperty); }
             set { SetValue(BaselineAlignmentProperty, value); }
         }
+        
+        /// <summary>
+        /// Gets the value of the attached <see cref="TextDecorationsProperty"/> on a control.
+        /// </summary>
+        /// <param name="control">The control.</param>
+        /// <returns>The font style.</returns>
+        public static TextDecorationCollection? GetTextDecorations(Control control)
+        {
+            return control.GetValue(TextDecorationsProperty);
+        }
 
+        /// <summary>
+        /// Sets the value of the attached <see cref="TextDecorationsProperty"/> on a control.
+        /// </summary>
+        /// <param name="control">The control.</param>
+        /// <param name="value">The property value to set.</param>
+        public static void SetTextDecorations(Control control, TextDecorationCollection? value)
+        {
+            control.SetValue(TextDecorationsProperty, value);
+        }
+        
         internal abstract void BuildTextRun(IList<TextRun> textRuns);
 
         internal abstract void AppendText(StringBuilder stringBuilder);

src/Avalonia.Controls/ItemsControl.cs

@@ -67,6 +67,9 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<IBinding?> DisplayMemberBindingProperty =
             AvaloniaProperty.Register<ItemsControl, IBinding?>(nameof(DisplayMemberBinding));
 
+        private static readonly AttachedProperty<ControlTheme?> AppliedItemContainerTheme =
+            AvaloniaProperty.RegisterAttached<ItemsControl, Control, ControlTheme?>("AppliedItemContainerTheme");
+
         /// <summary>
         /// Gets or sets the <see cref="IBinding"/> to use for binding to the display member of each item.
         /// </summary>
@@ -663,13 +666,26 @@ namespace Avalonia.Controls
 
         internal void PrepareItemContainer(Control container, object? item, int index)
         {
-            var itemContainerTheme = ItemContainerTheme;
-
-            if (itemContainerTheme is not null &&
-                !container.IsSet(ThemeProperty) &&
-                StyledElement.GetStyleKey(container) == itemContainerTheme.TargetType)
+            // If the container has no theme set, or we've already applied our ItemContainerTheme
+            // (and it hasn't changed since) then we're in control of the container's Theme and may
+            // need to update it.
+            if (!container.IsSet(ThemeProperty) || container.GetValue(AppliedItemContainerTheme) == container.Theme)
             {
-                container.Theme = itemContainerTheme;
+                var itemContainerTheme = ItemContainerTheme;
+
+                if (itemContainerTheme?.TargetType?.IsAssignableFrom(GetStyleKey(container)) == true)
+                {
+                    // We have an ItemContainerTheme and it matches the container. Set the Theme
+                    // property, and mark the container as having had ItemContainerTheme applied.
+                    container.SetCurrentValue(ThemeProperty, itemContainerTheme);
+                    container.SetValue(AppliedItemContainerTheme, itemContainerTheme);
+                }
+                else
+                {
+                    // Otherwise clear the theme and the AppliedItemContainerTheme property.
+                    container.ClearValue(ThemeProperty);
+                    container.ClearValue(AppliedItemContainerTheme);
+                }
             }
 
             if (item is not Control)

src/Avalonia.Controls/Primitives/AccessText.cs

@@ -3,6 +3,7 @@ using Avalonia.Input;
 using Avalonia.Reactive;
 using Avalonia.Media;
 using Avalonia.Media.TextFormatting;
+using System;
 
 namespace Avalonia.Controls.Primitives
 {
@@ -68,11 +69,15 @@ namespace Avalonia.Controls.Primitives
             if (underscore != -1 && ShowAccessKey)
             {
                 var rect = TextLayout!.HitTestTextPosition(underscore);
-                var offset = new Vector(0, -1.5);
+
+                var x1 = Math.Round(rect.Left, MidpointRounding.AwayFromZero);
+                var x2 = Math.Round(rect.Right, MidpointRounding.AwayFromZero);
+                var y = Math.Round(rect.Bottom, MidpointRounding.AwayFromZero) - 1.5;
+
                 context.DrawLine(
                     new Pen(Foreground, 1),
-                    rect.BottomLeft + offset,
-                    rect.BottomRight + offset);
+                    new Point(x1, y),
+                    new Point(x2, y));
             }
         }
 

src/Avalonia.Controls/Shapes/Polygon.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using Avalonia.Media;
+using Avalonia.Data;
 
 namespace Avalonia.Controls.Shapes
 {
@@ -15,9 +16,9 @@ namespace Avalonia.Controls.Shapes
 
         public Polygon()
         {
-            Points = new Points();
+            SetValue(PointsProperty, new Points(), BindingPriority.Template);
         }
-        
+
         public IList<Point> Points
         {
             get => GetValue(PointsProperty);

src/Avalonia.Controls/Shapes/Polyline.cs

@@ -1,9 +1,10 @@
 using System.Collections.Generic;
 using Avalonia.Media;
+using Avalonia.Data;
 
 namespace Avalonia.Controls.Shapes
 {
-    public class Polyline: Shape
+    public class Polyline : Shape
     {
         public static readonly StyledProperty<IList<Point>> PointsProperty =
             AvaloniaProperty.Register<Polyline, IList<Point>>("Points");
@@ -16,7 +17,7 @@ namespace Avalonia.Controls.Shapes
 
         public Polyline()
         {
-            Points = new Points();
+            SetValue(PointsProperty, new Points(), BindingPriority.Template);
         }
 
         public IList<Point> Points

src/Avalonia.Controls/TextBlock.cs

@@ -135,7 +135,7 @@ namespace Avalonia.Controls
         /// Defines the <see cref="TextDecorations"/> property.
         /// </summary>
         public static readonly StyledProperty<TextDecorationCollection?> TextDecorationsProperty =
-            AvaloniaProperty.Register<TextBlock, TextDecorationCollection?>(nameof(TextDecorations));
+            Inline.TextDecorationsProperty.AddOwner<TextBlock>();
 
         /// <summary>
         /// Defines the <see cref="Inlines"/> property.

src/Avalonia.Native/AvaloniaNativePlatform.cs

@@ -108,7 +108,7 @@ namespace Avalonia.Native
                 .Bind<IPlatformSettings>().ToConstant(new NativePlatformSettings(_factory.CreatePlatformSettings()))
                 .Bind<IWindowingPlatform>().ToConstant(this)
                 .Bind<IClipboard>().ToConstant(new ClipboardImpl(_factory.CreateClipboard()))
-                .Bind<IRenderTimer>().ToConstant(new DefaultRenderTimer(60))
+                .Bind<IRenderTimer>().ToConstant(new AvaloniaNativeRenderTimer(_factory.CreatePlatformRenderTimer()))
                 .Bind<IMountedVolumeInfoProvider>().ToConstant(new MacOSMountedVolumeInfoProvider())
                 .Bind<IPlatformDragSource>().ToConstant(new AvaloniaNativeDragSource(_factory))
                 .Bind<IPlatformLifetimeEventsImpl>().ToConstant(applicationPlatform)

src/Avalonia.Native/AvaloniaNativeRenderTimer.cs

@@ -0,0 +1,58 @@
+using System;
+using System.Diagnostics;
+using Avalonia.Native.Interop;
+using Avalonia.Rendering;
+#nullable enable
+
+namespace Avalonia.Native;
+
+internal sealed class AvaloniaNativeRenderTimer : NativeCallbackBase, IRenderTimer, IAvnActionCallback
+{
+    private readonly IAvnPlatformRenderTimer _platformRenderTimer;
+    private readonly Stopwatch _stopwatch;
+    private Action<TimeSpan>? _tick;
+    private int _subscriberCount;
+    private bool registered;
+
+    public AvaloniaNativeRenderTimer(IAvnPlatformRenderTimer platformRenderTimer)
+    {
+        _platformRenderTimer = platformRenderTimer;
+        _stopwatch = Stopwatch.StartNew();
+    }
+
+    public event Action<TimeSpan> Tick
+    {
+        add
+        {
+            _tick += value;
+
+            if (!registered)
+            {
+                registered = true;
+                _platformRenderTimer.RegisterTick(this);
+            }
+
+            if (_subscriberCount++ == 0)
+            {
+                _platformRenderTimer.Start();
+            }
+        }
+
+        remove
+        {
+            if (--_subscriberCount == 0)
+            {
+                _platformRenderTimer.Stop();
+            }
+
+            _tick -= value;
+        }
+    }
+
+    public bool RunsInBackground => _platformRenderTimer.RunsInBackground().FromComBool();
+
+    public void Run()
+    {
+        _tick?.Invoke(_stopwatch.Elapsed);
+    }
+}

src/Avalonia.Native/avn.idl

@@ -507,6 +507,7 @@ interface IAvaloniaNativeFactory : IUnknown
      HRESULT CreateApplicationCommands(IAvnApplicationCommands** ppv);
      HRESULT CreatePlatformSettings(IAvnPlatformSettings** ppv);
      HRESULT CreatePlatformBehaviorInhibition(IAvnPlatformBehaviorInhibition** ppv);
+     HRESULT CreatePlatformRenderTimer(IAvnPlatformRenderTimer** ppv);
 }
 
 [uuid(233e094f-9b9f-44a3-9a6e-6948bbdd9fb1)]
@@ -999,3 +1000,12 @@ interface IAvnPlatformBehaviorInhibition : IUnknown
 {
     void SetInhibitAppSleep(bool inhibitAppSleep, char* reason);
 }
+
+[uuid(22edf20d-5803-2d3f-9247-b4842e5e9322)]
+interface IAvnPlatformRenderTimer : IUnknown
+{
+    HRESULT RegisterTick(IAvnActionCallback* callback);
+    void Start();
+    void Stop();
+    bool RunsInBackground();
+}

tests/Avalonia.Controls.UnitTests/ItemsControlTests.cs

@@ -14,6 +14,7 @@ using Avalonia.Input;
 using Avalonia.Layout;
 using Avalonia.LogicalTree;
 using Avalonia.Markup.Xaml.Templates;
+using Avalonia.Media;
 using Avalonia.Styling;
 using Avalonia.UnitTests;
 using Avalonia.VisualTree;
@@ -128,6 +129,155 @@ namespace Avalonia.Controls.UnitTests
             Assert.Same(container.Theme, theme);
         }
 
+        [Fact]
+        public void Container_Should_Have_Theme_Set_To_ItemContainerTheme_With_Base_TargetType()
+        {
+            using var app = Start();
+            var theme = new ControlTheme { TargetType = typeof(Control) };
+            var target = CreateTarget(
+                itemsSource: new[] { "Foo" },
+                itemContainerTheme: theme);
+
+            var container = GetContainer(target);
+
+            Assert.Same(container.Theme, theme);
+        }
+
+        [Fact]
+        public void ItemContainerTheme_Can_Be_Changed()
+        {
+            using var app = Start();
+            
+            var theme1 = new ControlTheme 
+            { 
+                TargetType = typeof(ContentPresenter),
+                Setters = { new Setter(ContentPresenter.BackgroundProperty, Brushes.Red) }
+            };
+
+            var theme2 = new ControlTheme
+            {
+                TargetType = typeof(ContentPresenter),
+                Setters = { new Setter(ContentPresenter.BackgroundProperty, Brushes.Green) }
+            };
+
+            var target = CreateTarget(
+                itemsSource: new[] { "Foo" },
+                itemContainerTheme: theme1);
+
+            var container = GetContainer(target);
+
+            Assert.Same(container.Theme, theme1);
+            Assert.Equal(container.Background, Brushes.Red);
+
+            target.ItemContainerTheme = theme2;
+
+            container = GetContainer(target);
+            Assert.Same(container.Theme, theme2);
+            Assert.Equal(container.Background, Brushes.Green);
+        }
+
+        [Fact]
+        public void ItemContainerTheme_Can_Be_Changed_Virtualizing()
+        {
+            using var app = Start();
+
+            var theme1 = new ControlTheme
+            {
+                TargetType = typeof(ContentPresenter),
+                Setters = { new Setter(ContentPresenter.BackgroundProperty, Brushes.Red) }
+            };
+
+            var theme2 = new ControlTheme
+            {
+                TargetType = typeof(ContentPresenter),
+                Setters = { new Setter(ContentPresenter.BackgroundProperty, Brushes.Green) }
+            };
+
+            var itemsPanel = new FuncTemplate<Panel?>(() => new VirtualizingStackPanel());
+            var target = CreateTarget(
+                itemsSource: new[] { "Foo" },
+                itemContainerTheme: theme1,
+                itemsPanel: itemsPanel);
+
+            var container = GetContainer(target);
+
+            Assert.Same(container.Theme, theme1);
+            Assert.Equal(container.Background, Brushes.Red);
+
+            target.ItemContainerTheme = theme2;
+            Layout(target);
+
+            container = GetContainer(target);
+            Assert.Same(container.Theme, theme2);
+            Assert.Equal(container.Background, Brushes.Green);
+        }
+
+        [Fact]
+        public void ItemContainerTheme_Can_Be_Cleared()
+        {
+            using var app = Start();
+
+            var theme = new ControlTheme
+            {
+                TargetType = typeof(ContentPresenter),
+                Setters = { new Setter(ContentPresenter.BackgroundProperty, Brushes.Red) }
+            };
+
+            var target = CreateTarget(
+                itemsSource: new[] { "Foo" },
+                itemContainerTheme: theme);
+
+            var container = GetContainer(target);
+
+            Assert.Same(container.Theme, theme);
+            Assert.Equal(container.Background, Brushes.Red);
+
+            target.ItemContainerTheme = null;
+
+            container = GetContainer(target);
+            Assert.Null(container.Theme);
+            Assert.Null(container.Background);
+        }
+
+        [Fact]
+        public void ItemContainerTheme_Should_Not_Override_LocalValue_Theme()
+        {
+            using var app = Start();
+
+            var theme1 = new ControlTheme
+            {
+                TargetType = typeof(ContentPresenter),
+                Setters = { new Setter(ContentPresenter.BackgroundProperty, Brushes.Red) }
+            };
+
+            var theme2 = new ControlTheme
+            {
+                TargetType = typeof(Control),
+                Setters = { new Setter(ContentPresenter.BackgroundProperty, Brushes.Green) }
+            };
+
+            var items = new object[]
+            {
+                new ContentPresenter(),
+                new ContentPresenter
+                {
+                    Theme = theme2
+                },
+            };
+
+            var target = CreateTarget(
+                itemsSource: items,
+                itemContainerTheme: theme1);
+
+            Assert.Same(theme1, GetContainer(target, 0).Theme);
+            Assert.Same(theme2, GetContainer(target, 1).Theme);
+
+            target.ItemContainerTheme = null;
+
+            Assert.Null(GetContainer(target, 0).Theme);
+            Assert.Same(theme2, GetContainer(target, 1).Theme);
+        }
+
         [Fact]
         public void Container_Should_Have_LogicalParent_Set_To_ItemsControl()
         {
@@ -851,6 +1001,7 @@ namespace Avalonia.Controls.UnitTests
             IList? itemsSource = null,
             ControlTheme? itemContainerTheme = null,
             IDataTemplate? itemTemplate = null,
+            ITemplate<Panel?>? itemsPanel = null,
             IEnumerable<IDataTemplate>? dataTemplates = null,
             bool performLayout = true)
         {
@@ -861,6 +1012,7 @@ namespace Avalonia.Controls.UnitTests
                 itemsSource: itemsSource,
                 itemContainerTheme: itemContainerTheme,
                 itemTemplate: itemTemplate,
+                itemsPanel: itemsPanel,
                 dataTemplates: dataTemplates,
                 performLayout: performLayout);
         }

tests/Avalonia.Controls.UnitTests/TextBlockTests.cs

@@ -202,5 +202,26 @@ namespace Avalonia.Controls.UnitTests
                 Assert.Equal(0, target.Inlines.Count);
             }
         }
+        
+        [Fact]
+        public void Setting_TextDecorations_Should_Update_Inlines()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var target = new TextBlock();
+
+                target.Inlines.Add(new Run("Hello World"));
+
+                Assert.Equal(1, target.Inlines.Count);
+
+                Assert.Null(target.Inlines[0].TextDecorations);
+
+                var underline = TextDecorations.Underline;
+
+                target.TextDecorations = underline;
+
+                Assert.Equal(underline, target.Inlines[0].TextDecorations);
+            }
+        }
     }
 }