Merge remote-tracking branch 'origin/master' into pr/894-buttons-are-disabled-when-there-is-a-null-in-the-binding-chain-for-command-3

 Conflicts:
	tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Property.cs

.gitignore

@@ -162,7 +162,8 @@ $RECYCLE.BIN/
 #################
 ## Cake
 #################
-tools/
+tools/*
+!tools/packages.config
 .nuget
 artifacts/
 nuget

build.cake

@@ -11,7 +11,7 @@
 // TOOLS
 ///////////////////////////////////////////////////////////////////////////////
 
-#tool "nuget:?package=xunit.runner.console&version=2.1.0"
+#tool "nuget:?package=xunit.runner.console&version=2.2.0"
 #tool "nuget:?package=OpenCover"
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -98,7 +98,6 @@ Task("Clean")
     CleanDirectory(parameters.TestsRoot);
 });
 
-
 Task("Restore-NuGet-Packages")
     .IsDependentOn("Clean")
     .WithCriteria(parameters.IsRunningOnWindows)
@@ -171,23 +170,25 @@ void RunCoreTest(string dir, Parameters parameters, bool net461Only)
             continue;
         Information("Running for " + fw);
         DotNetCoreTest(System.IO.Path.Combine(dir, System.IO.Path.GetFileName(dir)+".csproj"),
-            new DotNetCoreTestSettings{Framework = fw});
+            new DotNetCoreTestSettings {
+                Configuration = parameters.Configuration,
+                Framework = fw
+            });
     }
 }
 
-
 Task("Run-Net-Core-Unit-Tests")
     .IsDependentOn("Clean")
     .Does(() => {
         RunCoreTest("./tests/Avalonia.Base.UnitTests", parameters, false);
-        RunCoreTest("./tests/Avalonia.Controls.UnitTests", parameters, true);
-        RunCoreTest("./tests/Avalonia.Input.UnitTests", parameters, true);
-        RunCoreTest("./tests/Avalonia.Interactivity.UnitTests", parameters, true);
-        RunCoreTest("./tests/Avalonia.Layout.UnitTests", parameters, true);
-        //RunCoreTest("./tests/Avalonia.Markup.UnitTests", parameters, true);
-        //RunCoreTest("./tests/Avalonia.Markup.Xaml.UnitTests", parameters, true);
-        RunCoreTest("./tests/Avalonia.Styling.UnitTests", parameters, true);
-        RunCoreTest("./tests/Avalonia.Visuals.UnitTests", parameters, true);
+        RunCoreTest("./tests/Avalonia.Controls.UnitTests", parameters, false);
+        RunCoreTest("./tests/Avalonia.Input.UnitTests", parameters, false);
+        RunCoreTest("./tests/Avalonia.Interactivity.UnitTests", parameters, false);
+        RunCoreTest("./tests/Avalonia.Layout.UnitTests", parameters, false);
+        RunCoreTest("./tests/Avalonia.Markup.UnitTests", parameters, false);
+        RunCoreTest("./tests/Avalonia.Markup.Xaml.UnitTests", parameters, false);
+        RunCoreTest("./tests/Avalonia.Styling.UnitTests", parameters, false);
+        RunCoreTest("./tests/Avalonia.Visuals.UnitTests", parameters, false);
     });
 
 Task("Run-Unit-Tests")

build/Moq.props

@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="Moq" Version="4.7.1" />
+    <PackageReference Include="Moq" Version="4.7.25" />
   </ItemGroup>
 </Project>

build/XUnit.props

@@ -7,7 +7,9 @@
     <PackageReference Include="xunit.extensibility.core" Version="2.2.0" />
     <PackageReference Include="xunit.extensibility.execution" Version="2.2.0" />
     <PackageReference Include="xunit.runner.console" Version="2.2.0" />
-    <PackageReference Condition="'$(TargetFramework)' == 'net461'" Include="xunit.runner.visualstudio" Version="2.2.0" />
-    <PackageReference Condition="'$(TargetFramework)' == 'netcoreapp1.1'" Include="Microsoft.NET.Test.Sdk" Version="15.0.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp1.1'">
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.0.0" />
   </ItemGroup>
 </Project>

docs/tutorial/from-wpf.md

@@ -33,7 +33,7 @@ placed in a `DataTemplates` collection on each control (and on `Application`):
                     <TextBox Text="{Binding Name}"/>
                 </Border>
             </DataTemplate>
-        </UserControl.Styles>
+        </UserControl.DataTemplates>
         <!-- Assuming that DataContext.Foo is an object of type
              MyApp.ViewModels.FooViewModel then a red border with a corner
              radius of 8 containing a TextBox will be displayed here -->

samples/interop/Direct3DInteropSample/Direct3DInteropSample.csproj

@@ -22,6 +22,7 @@
     <ItemGroup>
         <ProjectReference Include="..\..\..\src\Avalonia.DesignerSupport\Avalonia.DesignerSupport.csproj" />
         <ProjectReference Include="..\..\..\src\Avalonia.DotNetFrameworkRuntime\Avalonia.DotNetFrameworkRuntime.csproj" />
+        <ProjectReference Include="..\..\..\src\Avalonia.ReactiveUI\Avalonia.ReactiveUI.csproj" />
         <ProjectReference Include="..\..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
         <ProjectReference Include="..\..\..\src\Windows\Avalonia.Direct2D1\Avalonia.Direct2D1.csproj" />
         <ProjectReference Include="..\..\..\src\Windows\Avalonia.Win32\Avalonia.Win32.csproj" />

samples/interop/WindowsInteropTest/WindowsInteropTest.csproj

@@ -181,5 +181,6 @@
   </ItemGroup>
   <Import Project="..\..\..\build\Rx.props" />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <Import Project="..\..\..\build\SkiaSharp.props" />
   <Import Project="$(MSBuildThisFileDirectory)..\..\..\src\Shared\nuget.workaround.targets" />
 </Project>

src/Android/Avalonia.Android/AndroidPlatform.cs

@@ -51,7 +51,6 @@ namespace Avalonia.Android
                 .Bind<IClipboard>().ToTransient<ClipboardImpl>()
                 .Bind<IStandardCursorFactory>().ToTransient<CursorFactory>()
                 .Bind<IKeyboardDevice>().ToSingleton<AndroidKeyboardDevice>()
-                .Bind<IMouseDevice>().ToSingleton<AndroidMouseDevice>()
                 .Bind<IPlatformSettings>().ToConstant(Instance)
                 .Bind<IRendererFactory>().ToConstant(ImmediateRenderer.Factory)
                 .Bind<IPlatformThreadingInterface>().ToConstant(new AndroidThreadingInterface())

src/Android/Avalonia.Android/Platform/Input/AndroidMouseDevice.cs

@@ -4,6 +4,8 @@ namespace Avalonia.Android.Platform.Input
 {
     public class AndroidMouseDevice : MouseDevice
     {
+        public static AndroidMouseDevice Instance { get; } = new AndroidMouseDevice();
+
         public AndroidMouseDevice()
         {
 

src/Android/Avalonia.Android/Platform/SkiaPlatform/AndroidFramebuffer.cs

@@ -44,7 +44,7 @@ namespace Avalonia.Android.Platform.SkiaPlatform
         public int Width { get; }
         public int Height { get; }
         public int RowBytes { get; }
-        public Size Dpi { get; } = new Size(96, 96);
+        public Vector Dpi { get; } = new Vector(96, 96);
         public PixelFormat Format { get; }
 
         [DllImport("android")]

src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs

@@ -10,6 +10,7 @@ using Avalonia.Platform;
 using System;
 using System.Collections.Generic;
 using System.Reactive.Disposables;
+using Avalonia.Android.Platform.Input;
 using Avalonia.Controls;
 using Avalonia.Controls.Platform.Surfaces;
 
@@ -65,6 +66,8 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             }
         }
 
+        public IMouseDevice MouseDevice => AndroidMouseDevice.Instance;
+
         public Action Closed { get; set; }
 
         public Action<RawInputEventArgs> Input { get; set; }

src/Android/Avalonia.Android/Platform/Specific/Helpers/AndroidTouchEventsHelper.cs

@@ -71,7 +71,7 @@ namespace Avalonia.Android.Platform.Specific.Helpers
                 if (x <= _point.X && r >= _point.X && y <= _point.Y && b >= _point.Y)
                 {
                     var inputRoot = _getInputRoot();
-                    var mouseDevice = MouseDevice.Instance;
+                    var mouseDevice = Avalonia.Android.Platform.Input.AndroidMouseDevice.Instance;
 
                     //in order the controls to work in a predictable way
                     //we need to generate mouse move before first mouse down event

src/Avalonia.Base/Collections/AvaloniaListExtensions.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.ComponentModel;
@@ -59,7 +60,8 @@ namespace Avalonia.Collections
         /// the index in the collection and the item.
         /// </param>
         /// <param name="reset">
-        /// An action called when the collection is reset.
+        /// An action called when the collection is reset. This will be followed by calls to 
+        /// <paramref name="added"/> for each item present in the collection after the reset.
         /// </param>
         /// <returns>A disposable used to terminate the subscription.</returns>
         public static IDisposable ForEachItem<T>(
@@ -68,112 +70,38 @@ namespace Avalonia.Collections
             Action<int, T> removed,
             Action reset)
         {
-            int index;
-
-            NotifyCollectionChangedEventHandler handler = (_, e) =>
+            void Add(int index, IList items)
             {
-                switch (e.Action)
+                foreach (T item in items)
                 {
-                    case NotifyCollectionChangedAction.Add:
-                        index = e.NewStartingIndex;
-
-                        foreach (T item in e.NewItems)
-                        {
-                            added(index++, item);
-                        }
-
-                        break;
-
-                    case NotifyCollectionChangedAction.Replace:
-                        index = e.OldStartingIndex;
-
-                        foreach (T item in e.OldItems)
-                        {
-                            removed(index++, item);
-                        }
-
-                        index = e.NewStartingIndex;
-
-                        foreach (T item in e.NewItems)
-                        {
-                            added(index++, item);
-                        }
-
-                        break;
-
-                    case NotifyCollectionChangedAction.Remove:
-                        index = e.OldStartingIndex;
-
-                        foreach (T item in e.OldItems)
-                        {
-                            removed(index++, item);
-                        }
-
-                        break;
-
-                    case NotifyCollectionChangedAction.Reset:
-                        if (reset == null)
-                        {
-                            throw new InvalidOperationException(
-                                "Reset called on collection without reset handler.");
-                        }
-
-                        reset();
-                        break;
+                    added(index++, item);
                 }
-            };
+            }
 
-            index = 0;
-            foreach (T i in collection)
+            void Remove(int index, IList items)
             {
-                added(index++, i);
+                for (var i = items.Count - 1; i >= 0; --i)
+                {
+                    removed(index + i, (T)items[i]);
+                }
             }
 
-            collection.CollectionChanged += handler;
-
-            return Disposable.Create(() => collection.CollectionChanged -= handler);
-        }
-
-        /// <summary>
-        /// Invokes an action for each item in a collection and subsequently each item added or
-        /// removed from the collection.
-        /// </summary>
-        /// <typeparam name="T">The type of the collection items.</typeparam>
-        /// <param name="collection">The collection.</param>
-        /// <param name="added">
-        /// An action called initially with all items in the collection and subsequently with a
-        /// list of items added to the collection. The parameters passed are the index of the
-        /// first item added to the collection and the items added.
-        /// </param>
-        /// <param name="removed">
-        /// An action called with all items removed from the collection. The parameters passed 
-        /// are the index of the first item removed from the collection and the items removed.
-        /// </param>
-        /// <param name="reset">
-        /// An action called when the collection is reset.
-        /// </param>
-        /// <returns>A disposable used to terminate the subscription.</returns>
-        public static IDisposable ForEachItem<T>(
-            this IAvaloniaReadOnlyList<T> collection,
-            Action<int, IEnumerable<T>> added,
-            Action<int, IEnumerable<T>> removed,
-            Action reset)
-        {
             NotifyCollectionChangedEventHandler handler = (_, e) =>
             {
                 switch (e.Action)
                 {
                     case NotifyCollectionChangedAction.Add:
-                        added(e.NewStartingIndex, e.NewItems.Cast<T>());
+                        Add(e.NewStartingIndex, e.NewItems);
                         break;
 
+                    case NotifyCollectionChangedAction.Move:
                     case NotifyCollectionChangedAction.Replace:
-                        removed(e.OldStartingIndex, e.OldItems.Cast<T>());
-                        added(e.NewStartingIndex, e.NewItems.Cast<T>());
+                        Remove(e.OldStartingIndex, e.OldItems);
+                        Add(e.NewStartingIndex, e.NewItems);
                         break;
 
                     case NotifyCollectionChangedAction.Remove:
-                        removed(e.OldStartingIndex, e.OldItems.Cast<T>());
+                        Remove(e.OldStartingIndex, e.OldItems);
                         break;
 
                     case NotifyCollectionChangedAction.Reset:
@@ -184,16 +112,31 @@ namespace Avalonia.Collections
                         }
 
                         reset();
+                        Add(0, (IList)collection);
                         break;
                 }
             };
 
-            added(0, collection);
+            Add(0, (IList)collection);
             collection.CollectionChanged += handler;
 
             return Disposable.Create(() => collection.CollectionChanged -= handler);
         }
 
+        public static IAvaloniaReadOnlyList<TDerived> CreateDerivedList<TSource, TDerived>(
+            this IAvaloniaReadOnlyList<TSource> collection,
+            Func<TSource, TDerived> select)
+        {
+            var result = new AvaloniaList<TDerived>();
+
+            collection.ForEachItem(
+                (i, item) => result.Insert(i, select(item)),
+                (i, item) => result.RemoveAt(i),
+                () => result.Clear());
+
+            return result;
+        }
+
         /// <summary>
         /// Listens for property changed events from all items in a collection.
         /// </summary>

src/Avalonia.Base/Data/BindingNotification.cs

@@ -45,11 +45,7 @@ namespace Avalonia.Data
         public static readonly BindingNotification UnsetValue =
             new BindingNotification(AvaloniaProperty.UnsetValue);
 
-        // Null cannot be held in WeakReference as it's indistinguishable from an expired value so
-        // use this value in its place.
-        private static readonly object NullValue = new object();
-
-        private WeakReference<object> _value;
+        private object _value;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="BindingNotification"/> class.
@@ -57,7 +53,7 @@ namespace Avalonia.Data
         /// <param name="value">The binding value.</param>
         public BindingNotification(object value)
         {
-            _value = new WeakReference<object>(value ?? NullValue);
+            _value = value;
         }
 
         /// <summary>
@@ -74,6 +70,7 @@ namespace Avalonia.Data
 
             Error = error;
             ErrorType = errorType;
+            _value = AvaloniaProperty.UnsetValue;
         }
 
         /// <summary>
@@ -85,7 +82,7 @@ namespace Avalonia.Data
         public BindingNotification(Exception error, BindingErrorType errorType, object fallbackValue)
             : this(error, errorType)
         {
-            _value = new WeakReference<object>(fallbackValue ?? NullValue);
+            _value = fallbackValue;
         }
 
         /// <summary>
@@ -96,31 +93,12 @@ namespace Avalonia.Data
         /// If this property is read when <see cref="HasValue"/> is false then it will return
         /// <see cref="AvaloniaProperty.UnsetValue"/>.
         /// </remarks>
-        public object Value
-        {
-            get
-            {
-                if (_value != null)
-                {
-                    object result;
-
-                    if (_value.TryGetTarget(out result))
-                    {
-                        return result == NullValue ? null : result;
-                    }
-                }
-
-                // There's the possibility of a race condition in that HasValue can return true,
-                // and then the value is GC'd before Value is read. We should be ok though as
-                // we return UnsetValue which should be a safe alternative.
-                return AvaloniaProperty.UnsetValue;
-            }
-        }
+        public object Value => _value;
 
         /// <summary>
         /// Gets a value indicating whether <see cref="Value"/> should be pushed to the target.
         /// </summary>
-        public bool HasValue => _value != null;
+        public bool HasValue => _value != AvaloniaProperty.UnsetValue;
 
         /// <summary>
         /// Gets the error that occurred on the source, if any.
@@ -249,7 +227,7 @@ namespace Avalonia.Data
         /// </summary>
         public void ClearValue()
         {
-            _value = null;
+            _value = AvaloniaProperty.UnsetValue;
         }
 
         /// <summary>
@@ -257,7 +235,7 @@ namespace Avalonia.Data
         /// </summary>
         public void SetValue(object value)
         {
-            _value = new WeakReference<object>(value ?? NullValue);
+            _value = value;
         }
 
         /// <inheritdoc/>

src/Avalonia.Controls/Button.cs

@@ -238,7 +238,7 @@ namespace Avalonia.Controls
             PseudoClasses.Remove(":pressed");
             e.Handled = true;
 
-            if (ClickMode == ClickMode.Release && Classes.Contains(":pointerover"))
+            if (ClickMode == ClickMode.Release && new Rect(Bounds.Size).Contains(e.GetPosition(this)))
             {
                 RaiseClickEvent();
             }

src/Avalonia.Controls/Control.cs

@@ -118,6 +118,7 @@ namespace Avalonia.Controls
         public Control()
         {
             _nameScope = this as INameScope;
+            _isAttachedToLogicalTree = this is IStyleRoot;
         }
 
         /// <summary>
@@ -369,6 +370,12 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <inheritdoc/>
+        void ILogical.NotifyAttachedToLogicalTree(LogicalTreeAttachmentEventArgs e)
+        {
+            this.OnAttachedToLogicalTreeCore(e);
+        }
+
         /// <inheritdoc/>
         void ILogical.NotifyDetachedFromLogicalTree(LogicalTreeAttachmentEventArgs e)
         {
@@ -418,7 +425,7 @@ namespace Avalonia.Controls
 
                 if (_isAttachedToLogicalTree)
                 {
-                    var oldRoot = FindStyleRoot(old);
+                    var oldRoot = FindStyleRoot(old) ?? this as IStyleRoot;
 
                     if (oldRoot == null)
                     {
@@ -436,7 +443,7 @@ namespace Avalonia.Controls
 
                 _parent = (IControl)parent;
 
-                if (_parent is IStyleRoot || _parent?.IsAttachedToLogicalTree == true)
+                if (_parent is IStyleRoot || _parent?.IsAttachedToLogicalTree == true || this is IStyleRoot)
                 {
                     var newRoot = FindStyleRoot(this);
 
@@ -469,7 +476,7 @@ namespace Avalonia.Controls
             {
                 if (!IsInitialized)
                 {
-                    foreach (var i in this.GetSelfAndVisualDescendents())
+                    foreach (var i in this.GetSelfAndVisualDescendants())
                     {
                         var c = i as IControl;
 

src/Avalonia.Controls/Platform/ITopLevelImpl.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using Avalonia.Input;
 using Avalonia.Input.Raw;
+using JetBrains.Annotations;
 
 namespace Avalonia.Platform
 {
@@ -93,5 +94,11 @@ namespace Avalonia.Platform
         /// Gets or sets a method called when the underlying implementation is destroyed.
         /// </summary>
         Action Closed { get; set; }
+
+        /// <summary>
+        /// Gets a mouse device associated with toplevel
+        /// </summary>
+        [CanBeNull]
+        IMouseDevice MouseDevice { get; }
     }
 }

src/Avalonia.Controls/Presenters/ContentPresenter.cs

@@ -8,6 +8,7 @@ using Avalonia.Controls.Templates;
 using Avalonia.Layout;
 using Avalonia.LogicalTree;
 using Avalonia.Media;
+using Avalonia.VisualTree;
 
 namespace Avalonia.Controls.Presenters
 {
@@ -88,6 +89,7 @@ namespace Avalonia.Controls.Presenters
         static ContentPresenter()
         {
             ContentProperty.Changed.AddClassHandler<ContentPresenter>(x => x.ContentChanged);
+            ContentTemplateProperty.Changed.AddClassHandler<ContentPresenter>(x => x.ContentChanged);
             TemplatedParentProperty.Changed.AddClassHandler<ContentPresenter>(x => x.TemplatedParentChanged);
         }
 
@@ -313,27 +315,22 @@ namespace Avalonia.Controls.Presenters
 
             if (content != null && newChild == null)
             {
-                // We have content and it isn't a control, so first try to recycle the existing
-                // child control to display the new data by querying if the template that created
-                // the child can recycle items and that it also matches the new data.
-                if (oldChild != null &&
-                    _dataTemplate != null &&
-                    _dataTemplate.SupportsRecycling &&
-                    _dataTemplate.Match(content))
+                var dataTemplate = this.FindDataTemplate(content, ContentTemplate) ?? FuncDataTemplate.Default;
+
+                // We have content and it isn't a control, so if the new data template is the same
+                // as the old data template, try to recycle the existing child control to display
+                // the new data.
+                if (dataTemplate == _dataTemplate && dataTemplate.SupportsRecycling)
                 {
                     newChild = oldChild;
                 }
                 else
                 {
-                    // We couldn't recycle an existing control so find a data template for the data
-                    // and use it to create a control.
-                    _dataTemplate = this.FindDataTemplate(content, ContentTemplate) ?? FuncDataTemplate.Default;
+                    _dataTemplate = dataTemplate;
                     newChild = _dataTemplate.Build(content);
 
-                    // Try to give the new control its own name scope.
-                    var controlResult = newChild as Control;
-
-                    if (controlResult != null)
+                    // Give the new control its own name scope.
+                    if (newChild is Control controlResult)
                     {
                         NameScope.SetNameScope(controlResult, new NameScope());
                     }
@@ -424,6 +421,19 @@ namespace Avalonia.Controls.Presenters
         private void ContentChanged(AvaloniaPropertyChangedEventArgs e)
         {
             _createdChild = false;
+
+            if (((ILogical)this).IsAttachedToLogicalTree)
+            {
+                UpdateChild();
+            }
+            else if (Child != null)
+            {
+                VisualChildren.Remove(Child);
+                LogicalChildren.Remove(Child);
+                Child = null;
+                _dataTemplate = null;
+            }
+
             InvalidateMeasure();
         }
 

src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs

@@ -111,7 +111,7 @@ namespace Avalonia.Controls.Presenters
         /// <param name="target">The target visual.</param>
         /// <param name="targetRect">The portion of the target visual to bring into view.</param>
         /// <returns>True if the scroll offset was changed; otherwise false.</returns>
-        public bool BringDescendentIntoView(IVisual target, Rect targetRect)
+        public bool BringDescendantIntoView(IVisual target, Rect targetRect)
         {
             if (Child == null)
             {
@@ -262,7 +262,7 @@ namespace Avalonia.Controls.Presenters
 
         private void BringIntoViewRequested(object sender, RequestBringIntoViewEventArgs e)
         {
-            e.Handled = BringDescendentIntoView(e.TargetObject, e.TargetRect);
+            e.Handled = BringDescendantIntoView(e.TargetObject, e.TargetRect);
         }
 
         private void ChildChanged(AvaloniaPropertyChangedEventArgs e)

src/Avalonia.Controls/Primitives/Popup.cs

@@ -340,11 +340,11 @@ namespace Avalonia.Controls.Primitives
             switch (mode)
             {
                 case PlacementMode.Pointer:
-                    if (MouseDevice.Instance != null)
+                    if(PopupRoot != null)
                     {
                         // Scales the Horizontal and Vertical offset to screen co-ordinates.
                         var screenOffset = new Point(HorizontalOffset * (PopupRoot as ILayoutRoot).LayoutScaling, VerticalOffset * (PopupRoot as ILayoutRoot).LayoutScaling);
-                        return MouseDevice.Instance.Position + screenOffset;
+                        return (((IInputRoot)PopupRoot)?.MouseDevice?.Position ?? default(Point)) + screenOffset;
                     }
 
                     return default(Point);

src/Avalonia.Controls/Primitives/TemplatedControl.cs

@@ -285,6 +285,17 @@ namespace Avalonia.Controls.Primitives
             return this;
         }
 
+        /// <inheritdoc/>
+        protected override void OnAttachedToLogicalTree(LogicalTreeAttachmentEventArgs e)
+        {
+            if (VisualChildren.Count > 0)
+            {
+                ((ILogical)VisualChildren[0]).NotifyAttachedToLogicalTree(e);
+            }
+
+            base.OnAttachedToLogicalTree(e);
+        }
+
         /// <inheritdoc/>
         protected override void OnDetachedFromLogicalTree(LogicalTreeAttachmentEventArgs e)
         {

src/Avalonia.Controls/Templates/TemplateExtensions.cs

@@ -31,9 +31,9 @@ namespace Avalonia.Controls.Templates
 
                 if (child.TemplatedParent != null)
                 {
-                    foreach (var descendent in GetTemplateChildren(child, templatedParent))
+                    foreach (var descendant in GetTemplateChildren(child, templatedParent))
                     {
-                        yield return descendent;
+                        yield return descendant;
                     }
                 }
             }

src/Avalonia.Controls/ToolTip.cs

@@ -105,17 +105,21 @@ namespace Avalonia.Controls
         {
             if (control != null && control.IsVisible && control.GetVisualRoot() != null)
             {
-                if (s_popup != null)
+                var cp = (control.GetVisualRoot() as IInputRoot)?.MouseDevice?.GetPosition(control);
+                var position = control.PointToScreen(cp ?? new Point(0, 0)) + new Vector(0, 22);
+
+                if (s_popup == null)
                 {
-                    throw new AvaloniaInternalException("Previous ToolTip not disposed.");
+                    s_popup = new PopupRoot();
+                    s_popup.Content = new ToolTip();
+                }
+                else
+                {
+                    ((ISetLogicalParent)s_popup).SetParent(null);
                 }
 
-                var cp = MouseDevice.Instance?.GetPosition(control);
-                var position = control.PointToScreen(cp ?? new Point(0, 0)) + new Vector(0, 22);
-
-                s_popup = new PopupRoot();
                 ((ISetLogicalParent)s_popup).SetParent(control);
-                s_popup.Content = new ToolTip { Content = GetTip(control) };
+                ((ToolTip)s_popup.Content).Content = GetTip(control);
                 s_popup.Position = position;
                 s_popup.Show();
 
@@ -147,16 +151,23 @@ namespace Avalonia.Controls
             {
                 if (s_popup != null)
                 {
-                    // Clear the ToolTip's Content in case it has control content: this will
-                    // reset its visual parent allowing it to be used again.
-                    ((ToolTip)s_popup.Content).Content = null;
-
-                    // Dispose of the popup.
-                    s_popup.Dispose();
-                    s_popup = null;
+                    DisposeTooltip();
+                    s_show.OnNext(null);
                 }
+            }
+        }
+
+        private static void DisposeTooltip()
+        {
+            if (s_popup != null)
+            {
+                // Clear the ToolTip's Content in case it has control content: this will
+                // reset its visual parent allowing it to be used again.
+                ((ToolTip)s_popup.Content).Content = null;
 
-                s_show.OnNext(null);
+                // Dispose of the popup.
+                s_popup.Dispose();
+                s_popup = null;
             }
         }
     }

src/Avalonia.Controls/TopLevel.cs

@@ -163,6 +163,9 @@ namespace Avalonia.Controls
             set { SetValue(PointerOverElementProperty, value); }
         }
 
+        /// <inheritdoc/>
+        IMouseDevice IInputRoot.MouseDevice => PlatformImpl?.MouseDevice;
+
         /// <summary>
         /// Gets or sets a value indicating whether access keys are shown in the window.
         /// </summary>
@@ -253,7 +256,7 @@ namespace Avalonia.Controls
         /// <param name="scaling">The window scaling.</param>
         protected virtual void HandleScalingChanged(double scaling)
         {
-            foreach (ILayoutable control in this.GetSelfAndVisualDescendents())
+            foreach (ILayoutable control in this.GetSelfAndVisualDescendants())
             {
                 control.InvalidateMeasure();
             }

src/Avalonia.Controls/Window.cs

@@ -47,12 +47,12 @@ namespace Avalonia.Controls
     /// </summary>
     public class Window : WindowBase, IStyleable, IFocusScope, ILayoutRoot, INameScope
     {
-        private static IList<Window> s_windows = new List<Window>();
+        private static List<Window> s_windows = new List<Window>();
 
         /// <summary>
         /// Retrieves an enumeration of all Windows in the currently running application.
         /// </summary>
-        public static IList<Window> OpenWindows => s_windows;
+        public static IReadOnlyList<Window> OpenWindows => s_windows;
 
         /// <summary>
         /// Defines the <see cref="SizeToContent"/> property.
@@ -238,6 +238,11 @@ namespace Avalonia.Controls
         /// </summary>
         public override void Show()
         {
+            if (IsVisible)
+            {
+                return;
+            }
+
             s_windows.Add(this);
 
             EnsureInitialized();
@@ -272,6 +277,11 @@ namespace Avalonia.Controls
         /// </returns>
         public Task<TResult> ShowDialog<TResult>()
         {
+            if (IsVisible)
+            {
+                throw new InvalidOperationException("The window is already being shown.");
+            }
+
             s_windows.Add(this);
 
             EnsureInitialized();
@@ -360,6 +370,7 @@ namespace Avalonia.Controls
         protected override void HandleClosed()
         {
             IsVisible = false;
+            s_windows.Remove(this);
             base.HandleClosed();
         }
 

src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj

@@ -34,7 +34,6 @@
     <ProjectReference Include="..\Avalonia.Input\Avalonia.Input.csproj" />
     <ProjectReference Include="..\Avalonia.Interactivity\Avalonia.Interactivity.csproj" />
     <ProjectReference Include="..\Avalonia.Layout\Avalonia.Layout.csproj" />
-    <ProjectReference Include="..\Avalonia.ReactiveUI\Avalonia.ReactiveUI.csproj" />
     <ProjectReference Include="..\Avalonia.Visuals\Avalonia.Visuals.csproj" />
     <ProjectReference Include="..\Avalonia.Styling\Avalonia.Styling.csproj" />
     <ProjectReference Include="..\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />

src/Avalonia.Diagnostics/DevTools.xaml.cs

@@ -11,7 +11,6 @@ using Avalonia.Input.Raw;
 using Avalonia.Interactivity;
 using Avalonia.Markup.Xaml;
 using Avalonia.VisualTree;
-using ReactiveUI;
 
 namespace Avalonia
 {
@@ -74,7 +73,7 @@ namespace Avalonia.Diagnostics
                         Content = devTools,
                         DataTemplates = new DataTemplates
                         {
-                            new ViewLocator<ReactiveObject>(),
+                            new ViewLocator<ViewModelBase>(),
                         }
                     };
 
@@ -107,7 +106,8 @@ namespace Avalonia.Diagnostics
 
             if ((e.Modifiers) == modifiers)
             {
-                var point = MouseDevice.Instance.GetPosition(Root);
+
+                var point = (Root.VisualRoot as IInputRoot)?.MouseDevice?.GetPosition(Root) ?? default(Point);
                 var control = Root.GetVisualsAt(point, x => (!(x is AdornerLayer) && x.IsVisible))
                     .FirstOrDefault();
 

src/Avalonia.Diagnostics/ViewModels/ControlDetailsViewModel.cs

@@ -4,11 +4,10 @@
 using System.Collections.Generic;
 using System.Linq;
 using Avalonia.VisualTree;
-using ReactiveUI;
 
 namespace Avalonia.Diagnostics.ViewModels
 {
-    internal class ControlDetailsViewModel : ReactiveObject
+    internal class ControlDetailsViewModel : ViewModelBase
     {
         public ControlDetailsViewModel(IVisual control)
         {

src/Avalonia.Diagnostics/ViewModels/DevToolsViewModel.cs

@@ -5,32 +5,50 @@ using System;
 using System.Reactive.Linq;
 using Avalonia.Controls;
 using Avalonia.Input;
-using ReactiveUI;
 
 namespace Avalonia.Diagnostics.ViewModels
 {
-    internal class DevToolsViewModel : ReactiveObject
+    internal class DevToolsViewModel : ViewModelBase
     {
-        private ReactiveObject _content;
-
+        private ViewModelBase _content;
         private int _selectedTab;
-
         private TreePageViewModel _logicalTree;
-
         private TreePageViewModel _visualTree;
-
-        private readonly ObservableAsPropertyHelper<string> _focusedControl;
-
-        private readonly ObservableAsPropertyHelper<string> _pointerOverElement;
+        private string _focusedControl;
+        private string _pointerOverElement;
 
         public DevToolsViewModel(IControl root)
         {
             _logicalTree = new TreePageViewModel(LogicalTreeNode.Create(root));
             _visualTree = new TreePageViewModel(VisualTreeNode.Create(root));
 
-            this.WhenAnyValue(x => x.SelectedTab).Subscribe(index =>
+            UpdateFocusedControl();
+            KeyboardDevice.Instance.PropertyChanged += (s, e) =>
             {
-                switch (index)
+                if (e.PropertyName == nameof(KeyboardDevice.Instance.FocusedElement))
+                {
+                    UpdateFocusedControl();
+                }
+            };
+
+            root.GetObservable(TopLevel.PointerOverElementProperty)
+                .Subscribe(x => PointerOverElement = x?.GetType().Name);
+        }
+
+        public ViewModelBase Content
+        {
+            get { return _content; }
+            private set { RaiseAndSetIfChanged(ref _content, value); }
+        }
+
+        public int SelectedTab
+        {
+            get { return _selectedTab; }
+            set
+            {
+                _selectedTab = value;
+
+                switch (value)
                 {
                     case 0:
                         Content = _logicalTree;
@@ -39,34 +57,23 @@ namespace Avalonia.Diagnostics.ViewModels
                         Content = _visualTree;
                         break;
                 }
-            });
 
-            _focusedControl = KeyboardDevice.Instance
-                .WhenAnyValue(x => x.FocusedElement)
-                .Select(x => x?.GetType().Name)
-                .ToProperty(this, x => x.FocusedControl);
-
-            _pointerOverElement = root.GetObservable(TopLevel.PointerOverElementProperty)
-                .Select(x => x?.GetType().Name)
-                .ToProperty(this, x => x.PointerOverElement);
+                RaisePropertyChanged();
+            }
         }
 
-        public ReactiveObject Content
+        public string FocusedControl
         {
-            get { return _content; }
-            private set { this.RaiseAndSetIfChanged(ref _content, value); }
+            get { return _focusedControl; }
+            private set { RaiseAndSetIfChanged(ref _focusedControl, value); }
         }
 
-        public int SelectedTab
+        public string PointerOverElement
         {
-            get { return _selectedTab; }
-            set { this.RaiseAndSetIfChanged(ref _selectedTab, value); }
+            get { return _pointerOverElement; }
+            private set { RaiseAndSetIfChanged(ref _pointerOverElement, value); }
         }
 
-        public string FocusedControl => _focusedControl.Value;
-
-        public string PointerOverElement => _pointerOverElement.Value;
-
         public void SelectControl(IControl control)
         {
             var tree = Content as TreePageViewModel;
@@ -76,5 +83,10 @@ namespace Avalonia.Diagnostics.ViewModels
                 tree.SelectControl(control);
             }
         }
+
+        private void UpdateFocusedControl()
+        {
+            _focusedControl = KeyboardDevice.Instance.FocusedElement?.GetType().Name;
+        }
     }
 }

src/Avalonia.Diagnostics/ViewModels/LogicalTreeNode.cs

@@ -2,9 +2,9 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using Avalonia.Collections;
 using Avalonia.Controls;
 using Avalonia.LogicalTree;
-using ReactiveUI;
 
 namespace Avalonia.Diagnostics.ViewModels
 {
@@ -13,7 +13,7 @@ namespace Avalonia.Diagnostics.ViewModels
         public LogicalTreeNode(ILogical logical, TreeNode parent)
             : base((Control)logical, parent)
         {
-            Children = logical.LogicalChildren.CreateDerivedCollection(x => new LogicalTreeNode(x, this));
+            Children = logical.LogicalChildren.CreateDerivedList(x => new LogicalTreeNode(x, this));
         }
 
         public static LogicalTreeNode[] Create(object control)

src/Avalonia.Diagnostics/ViewModels/PropertyDetails.cs

@@ -3,16 +3,13 @@
 
 using System;
 using Avalonia.Data;
-using ReactiveUI;
 
 namespace Avalonia.Diagnostics.ViewModels
 {
-    internal class PropertyDetails : ReactiveObject
+    internal class PropertyDetails : ViewModelBase
     {
         private object _value;
-
         private string _priority;
-
         private string _diagnostic;
 
         public PropertyDetails(AvaloniaObject o, AvaloniaProperty property)
@@ -41,19 +38,19 @@ namespace Avalonia.Diagnostics.ViewModels
         public string Priority
         {
             get { return _priority; }
-            private set { this.RaiseAndSetIfChanged(ref _priority, value); }
+            private set { RaiseAndSetIfChanged(ref _priority, value); }
         }
 
         public string Diagnostic
         {
             get { return _diagnostic; }
-            private set { this.RaiseAndSetIfChanged(ref _diagnostic, value); }
+            private set { RaiseAndSetIfChanged(ref _diagnostic, value); }
         }
 
         public object Value
         {
             get { return _value; }
-            private set { this.RaiseAndSetIfChanged(ref _value, value); }
+            private set { RaiseAndSetIfChanged(ref _value, value); }
         }
     }
 }

src/Avalonia.Diagnostics/ViewModels/TreeNode.cs

@@ -5,13 +5,13 @@ using System;
 using System.Collections.Specialized;
 using System.Reactive;
 using System.Reactive.Linq;
+using Avalonia.Collections;
 using Avalonia.Styling;
 using Avalonia.VisualTree;
-using ReactiveUI;
 
 namespace Avalonia.Diagnostics.ViewModels
 {
-    internal class TreeNode : ReactiveObject
+    internal class TreeNode : ViewModelBase
     {
         private string _classes;
         private bool _isExpanded;
@@ -47,7 +47,7 @@ namespace Avalonia.Diagnostics.ViewModels
             }
         }
 
-        public IReadOnlyReactiveList<TreeNode> Children
+        public IAvaloniaReadOnlyList<TreeNode> Children
         {
             get;
             protected set;
@@ -56,7 +56,7 @@ namespace Avalonia.Diagnostics.ViewModels
         public string Classes
         {
             get { return _classes; }
-            private set { this.RaiseAndSetIfChanged(ref _classes, value); }
+            private set { RaiseAndSetIfChanged(ref _classes, value); }
         }
 
         public IVisual Visual
@@ -67,7 +67,7 @@ namespace Avalonia.Diagnostics.ViewModels
         public bool IsExpanded
         {
             get { return _isExpanded; }
-            set { this.RaiseAndSetIfChanged(ref _isExpanded, value); }
+            set { RaiseAndSetIfChanged(ref _isExpanded, value); }
         }
 
         public TreeNode Parent

src/Avalonia.Diagnostics/ViewModels/TreePageViewModel.cs

@@ -1,25 +1,19 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
-using System.Reactive.Linq;
 using Avalonia.Controls;
 using Avalonia.VisualTree;
-using ReactiveUI;
 
 namespace Avalonia.Diagnostics.ViewModels
 {
-    internal class TreePageViewModel : ReactiveObject
+    internal class TreePageViewModel : ViewModelBase
     {
         private TreeNode _selected;
-
-        private readonly ObservableAsPropertyHelper<ControlDetailsViewModel> _details;
+        private ControlDetailsViewModel _details;
 
         public TreePageViewModel(TreeNode[] nodes)
         {
             Nodes = nodes;
-            _details = this.WhenAnyValue(x => x.SelectedNode)
-                .Select(x => x != null ? new ControlDetailsViewModel(x.Visual) : null)
-                .ToProperty(this, x => x.Details);
         }
 
         public TreeNode[] Nodes { get; protected set; }
@@ -27,10 +21,20 @@ namespace Avalonia.Diagnostics.ViewModels
         public TreeNode SelectedNode
         {
             get { return _selected; }
-            set { this.RaiseAndSetIfChanged(ref _selected, value); }
+            set
+            {
+                if (RaiseAndSetIfChanged(ref _selected, value))
+                {
+                    Details = value != null ? new ControlDetailsViewModel(value.Visual) : null;
+                }
+            }
         }
 
-        public ControlDetailsViewModel Details => _details.Value;
+        public ControlDetailsViewModel Details
+        {
+            get { return _details; }
+            private set { RaiseAndSetIfChanged(ref _details, value); }
+        }
 
         public TreeNode FindNode(IControl control)
         {

src/Avalonia.Diagnostics/ViewModels/ViewModelBase.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
+using JetBrains.Annotations;
+
+namespace Avalonia.Diagnostics.ViewModels
+{
+    public class ViewModelBase : INotifyPropertyChanged
+    {
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        [NotifyPropertyChangedInvocator]
+        protected bool RaiseAndSetIfChanged<T>(ref T field, T value, [CallerMemberName] string propertyName = null)
+        {
+            if (!EqualityComparer<T>.Default.Equals(field, value))
+            {
+                field = value;
+                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+                return true;
+            }
+
+            return false;
+        }
+
+        [NotifyPropertyChangedInvocator]
+        protected void RaisePropertyChanged([CallerMemberName] string propertyName = null)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+    }
+}

src/Avalonia.Diagnostics/ViewModels/VisualTreeNode.cs

@@ -1,10 +1,9 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
-using Avalonia.Controls;
+using Avalonia.Collections;
 using Avalonia.Styling;
 using Avalonia.VisualTree;
-using ReactiveUI;
 
 namespace Avalonia.Diagnostics.ViewModels
 {
@@ -17,11 +16,11 @@ namespace Avalonia.Diagnostics.ViewModels
 
             if (host?.Root == null)
             {
-                Children = visual.VisualChildren.CreateDerivedCollection(x => new VisualTreeNode(x, this));
+                Children = visual.VisualChildren.CreateDerivedList(x => new VisualTreeNode(x, this));
             }
             else
             {
-                Children = new ReactiveList<VisualTreeNode>(new[] { new VisualTreeNode(host.Root, this) });
+                Children = new AvaloniaList<VisualTreeNode>(new[] { new VisualTreeNode(host.Root, this) });
             }
 
             if ((Visual is IStyleable styleable))

src/Avalonia.Diagnostics/Views/ControlDetailsView.cs

@@ -8,7 +8,6 @@ using Avalonia.Controls;
 using Avalonia.Diagnostics.ViewModels;
 using Avalonia.Media;
 using Avalonia.Styling;
-using ReactiveUI;
 
 namespace Avalonia.Diagnostics.Views
 {
@@ -16,6 +15,7 @@ namespace Avalonia.Diagnostics.Views
     {
         private static readonly StyledProperty<ControlDetailsViewModel> ViewModelProperty =
             AvaloniaProperty.Register<ControlDetailsView, ControlDetailsViewModel>("ViewModel");
+        private SimpleGrid _grid;
 
         public ControlDetailsView()
         {
@@ -27,7 +27,11 @@ namespace Avalonia.Diagnostics.Views
         public ControlDetailsViewModel ViewModel
         {
             get { return GetValue(ViewModelProperty); }
-            private set { SetValue(ViewModelProperty, value); }
+            private set
+            {
+                SetValue(ViewModelProperty, value);
+                _grid[GridRepeater.ItemsProperty] = value?.Properties;
+            }
         }
 
         private void InitializeComponent()
@@ -36,7 +40,7 @@ namespace Avalonia.Diagnostics.Views
 
             Content = new ScrollViewer
             {
-                Content = new SimpleGrid
+                Content = _grid = new SimpleGrid
                 {
                     Styles = new Styles
                     {
@@ -49,7 +53,6 @@ namespace Avalonia.Diagnostics.Views
                         },
                     },
                     [GridRepeater.TemplateProperty] = pt,
-                    [!GridRepeater.ItemsProperty] = this.WhenAnyValue(x => x.ViewModel.Properties).ToBinding(),
                 }
             };
         }
@@ -62,16 +65,13 @@ namespace Avalonia.Diagnostics.Views
             {
                 Text = property.Name,
                 TextWrapping = TextWrapping.NoWrap,
-                [!ToolTip.TipProperty] = property
-                    .WhenAnyValue(x => x.Diagnostic)
-                    .ToBinding(),
+                [!ToolTip.TipProperty] = property.GetObservable<string>(nameof(property.Diagnostic)).ToBinding(),
             };
 
             yield return new TextBlock
             {
                 TextWrapping = TextWrapping.NoWrap,
-                [!TextBlock.TextProperty] = property
-                    .WhenAnyValue(v => v.Value)
+                [!TextBlock.TextProperty] = property.GetObservable<object>(nameof(property.Value))
                     .Select(v => v?.ToString())
                     .ToBinding(),
             };
@@ -79,7 +79,7 @@ namespace Avalonia.Diagnostics.Views
             yield return new TextBlock
             {
                 TextWrapping = TextWrapping.NoWrap,
-                [!TextBlock.TextProperty] = property.WhenAnyValue(x => x.Priority).ToBinding(),
+                [!TextBlock.TextProperty] = property.GetObservable<string>((nameof(property.Priority))).ToBinding(),
             };
         }
     }

src/Avalonia.Diagnostics/Views/PropertyChangedExtenions.cs

@@ -0,0 +1,30 @@
+using System;
+using System.ComponentModel;
+using System.Reactive.Linq;
+using System.Reflection;
+
+namespace Avalonia.Diagnostics.Views
+{
+    internal static class PropertyChangedExtenions
+    {
+        public static IObservable<T> GetObservable<T>(this INotifyPropertyChanged source, string propertyName)
+        {
+            Contract.Requires<ArgumentNullException>(source != null);
+            Contract.Requires<ArgumentNullException>(propertyName != null);
+
+            var property = source.GetType().GetTypeInfo().GetDeclaredProperty(propertyName);
+
+            if (property == null)
+            {
+                throw new ArgumentException($"Property '{propertyName}' not found on '{source}.");
+            }
+
+            return Observable.FromEventPattern<PropertyChangedEventHandler, PropertyChangedEventArgs>(
+                e => source.PropertyChanged += e,
+                e => source.PropertyChanged -= e)
+                    .Where(e => e.EventArgs.PropertyName == propertyName)
+                    .Select(_ => (T)property.GetValue(source))
+                    .StartWith((T)property.GetValue(source));
+        }
+    }
+}

src/Avalonia.HtmlRenderer/Adapters/ControlAdapter.cs

@@ -10,9 +10,11 @@
 // - Sun Tsu,
 // "The Art of War"
 
+using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.Html;
 using Avalonia.Input;
+using Avalonia.VisualTree;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
@@ -54,7 +56,8 @@ namespace TheArtOfDev.HtmlRenderer.Avalonia.Adapters
         {
             get
             {
-                return Util.Convert(MouseDevice.Instance.GetPosition(_control));
+                var pos = (_control.GetVisualRoot() as IInputRoot)?.MouseDevice?.Position ?? default(Point);
+                return Util.Convert(pos);
             }
         }
 

src/Avalonia.HtmlRenderer/HtmlControl.cs

@@ -17,6 +17,7 @@ using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.Threading;
+using Avalonia.VisualTree;
 using TheArtOfDev.HtmlRenderer.Core;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
 using TheArtOfDev.HtmlRenderer.Avalonia;
@@ -512,7 +513,7 @@ namespace Avalonia.Controls.Html
         protected virtual void InvokeMouseMove()
         {
 
-            _htmlContainer.HandleMouseMove(this, MouseDevice.Instance?.GetPosition(this) ?? default(Point));
+            _htmlContainer.HandleMouseMove(this, (this.GetVisualRoot() as IInputRoot)?.MouseDevice?.GetPosition(this) ?? default(Point));
         }
 
         /// <summary>

src/Avalonia.Input/IInputDevice.cs

@@ -1,9 +1,16 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using Avalonia.Input.Raw;
+
 namespace Avalonia.Input
 {
     public interface IInputDevice
     {
+        /// <summary>
+        /// Processes raw event. Is called after preprocessing by InputManager
+        /// </summary>
+        /// <param name="ev"></param>
+        void ProcessRawEvent(RawInputEventArgs ev);
     }
 }

src/Avalonia.Input/IInputRoot.cs

@@ -1,6 +1,8 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using JetBrains.Annotations;
+
 namespace Avalonia.Input
 {
     /// <summary>
@@ -27,5 +29,11 @@ namespace Avalonia.Input
         /// Gets or sets a value indicating whether access keys are shown in the window.
         /// </summary>
         bool ShowAccessKeys { get; set; }
+
+        /// <summary>
+        /// Gets associated mouse device
+        /// </summary>
+        [CanBeNull]
+        IMouseDevice MouseDevice { get; }
     }
 }

src/Avalonia.Input/IKeyboardDevice.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using System.ComponentModel;
 
 namespace Avalonia.Input
 {
@@ -26,7 +27,7 @@ namespace Avalonia.Input
         Toggled = 2,
     }
 
-    public interface IKeyboardDevice : IInputDevice
+    public interface IKeyboardDevice : IInputDevice, INotifyPropertyChanged
     {
         IInputElement FocusedElement { get; }
 

src/Avalonia.Input/InputManager.cs

@@ -35,6 +35,7 @@ namespace Avalonia.Input
         public void ProcessInput(RawInputEventArgs e)
         {
             _preProcess.OnNext(e);
+            e.Device?.ProcessRawEvent(e);
             _process.OnNext(e);
             _postProcess.OnNext(e);
         }

src/Avalonia.Input/KeyboardDevice.cs

@@ -16,14 +16,6 @@ namespace Avalonia.Input
     {
         private IInputElement _focusedElement;
 
-        public KeyboardDevice()
-        {
-            InputManager.Process
-                .OfType<RawInputEventArgs>()
-                .Where(e => e.Device == this && !e.Handled)
-                .Subscribe(ProcessRawEvent);
-        }
-
         public event PropertyChangedEventHandler PropertyChanged;
 
         public static IKeyboardDevice Instance => AvaloniaLocator.Current.GetService<IKeyboardDevice>();
@@ -77,8 +69,10 @@ namespace Avalonia.Input
             PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
         }
 
-        private void ProcessRawEvent(RawInputEventArgs e)
+        public void ProcessRawEvent(RawInputEventArgs e)
         {
+            if(e.Handled)
+                return;
             IInputElement element = FocusedElement;
 
             if (element != null)

src/Avalonia.Input/MouseDevice.cs

@@ -20,23 +20,7 @@ namespace Avalonia.Input
         private int _clickCount;
         private Rect _lastClickRect;
         private uint _lastClickTime;
-
-        /// <summary>
-        /// Intializes a new instance of <see cref="MouseDevice"/>.
-        /// </summary>
-        public MouseDevice()
-        {
-            InputManager.Process
-                .OfType<RawMouseEventArgs>()
-                .Where(e => e.Device == this && !e.Handled)
-                .Subscribe(ProcessRawEvent);
-        }
-
-        /// <summary>
-        /// Gets the current mouse device instance.
-        /// </summary>
-        public static IMouseDevice Instance => AvaloniaLocator.Current.GetService<IMouseDevice>();
-
+       
         /// <summary>
         /// Gets the control that is currently capturing by the mouse, if any.
         /// </summary>
@@ -50,12 +34,7 @@ namespace Avalonia.Input
             get;
             protected set;
         }
-
-        /// <summary>
-        /// Gets the application's input manager.
-        /// </summary>
-        public IInputManager InputManager => AvaloniaLocator.Current.GetService<IInputManager>();
-
+        
         /// <summary>
         /// Gets the mouse position, in screen coordinates.
         /// </summary>
@@ -102,6 +81,12 @@ namespace Avalonia.Input
             return root.PointToClient(Position) - p;
         }
 
+        public void ProcessRawEvent(RawInputEventArgs e)
+        {
+            if (!e.Handled && e is RawMouseEventArgs margs)
+                ProcessRawEvent(margs);
+        }
+
         private void ProcessRawEvent(RawMouseEventArgs e)
         {
             Contract.Requires<ArgumentNullException>(e != null);

src/Avalonia.Input/Navigation/DirectionalNavigation.cs

@@ -44,7 +44,7 @@ namespace Avalonia.Input.Navigation
                                GetFirstInNextContainer(element, direction);
                     case KeyboardNavigationMode.Cycle:
                         return GetNextInContainer(element, container, direction) ??
-                               GetFocusableDescendent(container, direction);
+                               GetFocusableDescendant(container, direction);
                     case KeyboardNavigationMode.Contained:
                         return GetNextInContainer(element, container, direction);
                     default:
@@ -53,7 +53,7 @@ namespace Avalonia.Input.Navigation
             }
             else
             {
-                return GetFocusableDescendents(element).FirstOrDefault();
+                return GetFocusableDescendants(element).FirstOrDefault();
             }
         }
 
@@ -71,24 +71,24 @@ namespace Avalonia.Input.Navigation
         }
 
         /// <summary>
-        /// Gets the first or last focusable descendent of the specified element.
+        /// Gets the first or last focusable descendant of the specified element.
         /// </summary>
         /// <param name="container">The element.</param>
         /// <param name="direction">The direction to search.</param>
         /// <returns>The element or null if not found.##</returns>
-        private static IInputElement GetFocusableDescendent(IInputElement container, NavigationDirection direction)
+        private static IInputElement GetFocusableDescendant(IInputElement container, NavigationDirection direction)
         {
             return IsForward(direction) ?
-                GetFocusableDescendents(container).FirstOrDefault() :
-                GetFocusableDescendents(container).LastOrDefault();
+                GetFocusableDescendants(container).FirstOrDefault() :
+                GetFocusableDescendants(container).LastOrDefault();
         }
 
         /// <summary>
-        /// Gets the focusable descendents of the specified element.
+        /// Gets the focusable descendants of the specified element.
         /// </summary>
         /// <param name="element">The element.</param>
-        /// <returns>The element's focusable descendents.</returns>
-        private static IEnumerable<IInputElement> GetFocusableDescendents(IInputElement element)
+        /// <returns>The element's focusable descendants.</returns>
+        private static IEnumerable<IInputElement> GetFocusableDescendants(IInputElement element)
         {
             var children = element.GetVisualChildren().OfType<IInputElement>();
 
@@ -99,11 +99,11 @@ namespace Avalonia.Input.Navigation
                     yield return child;
                 }
 
-                if (child.CanFocusDescendents())
+                if (child.CanFocusDescendants())
                 {
-                    foreach (var descendent in GetFocusableDescendents(child))
+                    foreach (var descendant in GetFocusableDescendants(child))
                     {
-                        yield return descendent;
+                        yield return descendant;
                     }
                 }
             }
@@ -123,11 +123,11 @@ namespace Avalonia.Input.Navigation
         {
             if (direction == NavigationDirection.Down)
             {
-                var descendent = GetFocusableDescendents(element).FirstOrDefault();
+                var descendant = GetFocusableDescendants(element).FirstOrDefault();
 
-                if (descendent != null)
+                if (descendant != null)
                 {
-                    return descendent;
+                    return descendant;
                 }
             }
 
@@ -156,11 +156,11 @@ namespace Avalonia.Input.Navigation
 
                 if (element != null && direction == NavigationDirection.Up)
                 {
-                    var descendent = GetFocusableDescendents(element).LastOrDefault();
+                    var descendant = GetFocusableDescendants(element).LastOrDefault();
 
-                    if (descendent != null)
+                    if (descendant != null)
                     {
-                        return descendent;
+                        return descendant;
                     }
                 }
 
@@ -193,7 +193,7 @@ namespace Avalonia.Input.Navigation
 
                 var siblings = parent.GetVisualChildren()
                     .OfType<IInputElement>()
-                    .Where(FocusExtensions.CanFocusDescendents);
+                    .Where(FocusExtensions.CanFocusDescendants);
                 var sibling = isForward ? 
                     siblings.SkipWhile(x => x != container).Skip(1).FirstOrDefault() : 
                     siblings.TakeWhile(x => x != container).LastOrDefault();
@@ -207,8 +207,8 @@ namespace Avalonia.Input.Navigation
                     else
                     {
                         next = isForward ?
-                            GetFocusableDescendents(sibling).FirstOrDefault() :
-                            GetFocusableDescendents(sibling).LastOrDefault();
+                            GetFocusableDescendants(sibling).FirstOrDefault() :
+                            GetFocusableDescendants(sibling).LastOrDefault();
                     }
                 }
 
@@ -220,8 +220,8 @@ namespace Avalonia.Input.Navigation
             else
             {
                 next = isForward ?
-                    GetFocusableDescendents(container).FirstOrDefault() :
-                    GetFocusableDescendents(container).LastOrDefault();
+                    GetFocusableDescendants(container).FirstOrDefault() :
+                    GetFocusableDescendants(container).LastOrDefault();
             }
 
             return next;

src/Avalonia.Input/Navigation/FocusExtensions.cs

@@ -16,10 +16,10 @@ namespace Avalonia.Input.Navigation
         public static bool CanFocus(this IInputElement e) => e.Focusable && e.IsEnabledCore && e.IsVisible;
 
         /// <summary>
-        /// Checks if descendents of the specified element can be focused.
+        /// Checks if descendants of the specified element can be focused.
         /// </summary>
         /// <param name="e">The element.</param>
-        /// <returns>True if descendents of the element can be focused.</returns>
-        public static bool CanFocusDescendents(this IInputElement e) => e.IsEnabledCore && e.IsVisible;
+        /// <returns>True if descendants of the element can be focused.</returns>
+        public static bool CanFocusDescendants(this IInputElement e) => e.IsEnabledCore && e.IsVisible;
     }
 }

src/Avalonia.Input/Navigation/TabNavigation.cs

@@ -44,7 +44,7 @@ namespace Avalonia.Input.Navigation
                                GetFirstInNextContainer(element, direction);
                     case KeyboardNavigationMode.Cycle:
                         return GetNextInContainer(element, container, direction) ??
-                               GetFocusableDescendent(container, direction);
+                               GetFocusableDescendant(container, direction);
                     case KeyboardNavigationMode.Contained:
                         return GetNextInContainer(element, container, direction);
                     default:
@@ -53,29 +53,29 @@ namespace Avalonia.Input.Navigation
             }
             else
             {
-                return GetFocusableDescendents(element).FirstOrDefault();
+                return GetFocusableDescendants(element).FirstOrDefault();
             }
         }
 
         /// <summary>
-        /// Gets the first or last focusable descendent of the specified element.
+        /// Gets the first or last focusable descendant of the specified element.
         /// </summary>
         /// <param name="container">The element.</param>
         /// <param name="direction">The direction to search.</param>
         /// <returns>The element or null if not found.##</returns>
-        private static IInputElement GetFocusableDescendent(IInputElement container, NavigationDirection direction)
+        private static IInputElement GetFocusableDescendant(IInputElement container, NavigationDirection direction)
         {
             return direction == NavigationDirection.Next ?
-                GetFocusableDescendents(container).FirstOrDefault() :
-                GetFocusableDescendents(container).LastOrDefault();
+                GetFocusableDescendants(container).FirstOrDefault() :
+                GetFocusableDescendants(container).LastOrDefault();
         }
 
         /// <summary>
-        /// Gets the focusable descendents of the specified element.
+        /// Gets the focusable descendants of the specified element.
         /// </summary>
         /// <param name="element">The element.</param>
-        /// <returns>The element's focusable descendents.</returns>
-        private static IEnumerable<IInputElement> GetFocusableDescendents(IInputElement element)
+        /// <returns>The element's focusable descendants.</returns>
+        private static IEnumerable<IInputElement> GetFocusableDescendants(IInputElement element)
         {
             var mode = KeyboardNavigation.GetTabNavigation((InputElement)element);
 
@@ -108,11 +108,11 @@ namespace Avalonia.Input.Navigation
                     yield return child;
                 }
 
-                if (child.CanFocusDescendents())
+                if (child.CanFocusDescendants())
                 {
-                    foreach (var descendent in GetFocusableDescendents(child))
+                    foreach (var descendant in GetFocusableDescendants(child))
                     {
-                        yield return descendent;
+                        yield return descendant;
                     }
                 }
             }
@@ -132,11 +132,11 @@ namespace Avalonia.Input.Navigation
         {
             if (direction == NavigationDirection.Next)
             {
-                var descendent = GetFocusableDescendents(element).FirstOrDefault();
+                var descendant = GetFocusableDescendants(element).FirstOrDefault();
 
-                if (descendent != null)
+                if (descendant != null)
                 {
-                    return descendent;
+                    return descendant;
                 }
             }
 
@@ -167,11 +167,11 @@ namespace Avalonia.Input.Navigation
 
                 if (element != null && direction == NavigationDirection.Previous)
                 {
-                    var descendent = GetFocusableDescendents(element).LastOrDefault();
+                    var descendant = GetFocusableDescendants(element).LastOrDefault();
 
-                    if (descendent != null)
+                    if (descendant != null)
                     {
-                        return descendent;
+                        return descendant;
                     }
                 }
 
@@ -203,7 +203,7 @@ namespace Avalonia.Input.Navigation
 
                 var siblings = parent.GetVisualChildren()
                     .OfType<IInputElement>()
-                    .Where(FocusExtensions.CanFocusDescendents);
+                    .Where(FocusExtensions.CanFocusDescendants);
                 var sibling = direction == NavigationDirection.Next ? 
                     siblings.SkipWhile(x => x != container).Skip(1).FirstOrDefault() : 
                     siblings.TakeWhile(x => x != container).LastOrDefault();
@@ -217,8 +217,8 @@ namespace Avalonia.Input.Navigation
                     else
                     {
                         next = direction == NavigationDirection.Next ?
-                            GetFocusableDescendents(sibling).FirstOrDefault() :
-                            GetFocusableDescendents(sibling).LastOrDefault();
+                            GetFocusableDescendants(sibling).FirstOrDefault() :
+                            GetFocusableDescendants(sibling).LastOrDefault();
                     }
                 }
 
@@ -230,8 +230,8 @@ namespace Avalonia.Input.Navigation
             else
             {
                 next = direction == NavigationDirection.Next ?
-                    GetFocusableDescendents(container).FirstOrDefault() :
-                    GetFocusableDescendents(container).LastOrDefault();
+                    GetFocusableDescendants(container).FirstOrDefault() :
+                    GetFocusableDescendants(container).LastOrDefault();
             }
 
             return next;

src/Avalonia.Layout/LayoutManager.cs

@@ -14,8 +14,8 @@ namespace Avalonia.Layout
     /// </summary>
     public class LayoutManager : ILayoutManager
     {
-        private readonly HashSet<ILayoutable> _toMeasure = new HashSet<ILayoutable>();
-        private readonly HashSet<ILayoutable> _toArrange = new HashSet<ILayoutable>();
+        private readonly Queue<ILayoutable> _toMeasure = new Queue<ILayoutable>();
+        private readonly Queue<ILayoutable> _toArrange = new Queue<ILayoutable>();
         private bool _queued;
         private bool _running;
 
@@ -30,8 +30,18 @@ namespace Avalonia.Layout
             Contract.Requires<ArgumentNullException>(control != null);
             Dispatcher.UIThread.VerifyAccess();
 
-            _toMeasure.Add(control);
-            _toArrange.Add(control);
+            if (!control.IsAttachedToVisualTree)
+            {
+#if DEBUG
+                throw new AvaloniaInternalException(
+                    "LayoutManager.InvalidateMeasure called on a control that is detached from the visual tree.");
+#else
+                return;
+#endif
+            }
+
+            _toMeasure.Enqueue(control);
+            _toArrange.Enqueue(control);
             QueueLayoutPass();
         }
 
@@ -41,7 +51,17 @@ namespace Avalonia.Layout
             Contract.Requires<ArgumentNullException>(control != null);
             Dispatcher.UIThread.VerifyAccess();
 
-            _toArrange.Add(control);
+            if (!control.IsAttachedToVisualTree)
+            {
+#if DEBUG
+                throw new AvaloniaInternalException(
+                    "LayoutManager.InvalidateArrange called on a control that is detached from the visual tree.");
+#else
+                return;
+#endif
+            }
+
+            _toArrange.Enqueue(control);
             QueueLayoutPass();
         }
 
@@ -108,8 +128,12 @@ namespace Avalonia.Layout
         {
             while (_toMeasure.Count > 0)
             {
-                var next = _toMeasure.First();
-                Measure(next);
+                var control = _toMeasure.Dequeue();
+
+                if (!control.IsMeasureValid && control.IsAttachedToVisualTree)
+                {
+                    Measure(control);
+                }
             }
         }
 
@@ -117,53 +141,60 @@ namespace Avalonia.Layout
         {
             while (_toArrange.Count > 0 && _toMeasure.Count == 0)
             {
-                var next = _toArrange.First();
-                Arrange(next);
+                var control = _toArrange.Dequeue();
+
+                if (!control.IsArrangeValid && control.IsAttachedToVisualTree)
+                {
+                    Arrange(control);
+                }
             }
         }
 
         private void Measure(ILayoutable control)
         {
-            var root = control as ILayoutRoot;
-            var parent = control.VisualParent as ILayoutable;
-
-            if (root != null)
-            {
-                root.Measure(root.MaxClientSize);
-            }
-            else if (parent != null)
+            // Controls closest to the visual root need to be arranged first. We don't try to store
+            // ordered invalidation lists, instead we traverse the tree upwards, measuring the
+            // controls closest to the root first. This has been shown by benchmarks to be the
+            // fastest and most memory-efficent algorithm.
+            if (control.VisualParent is ILayoutable parent)
             {
                 Measure(parent);
             }
 
-            if (!control.IsMeasureValid)
+            // If the control being measured has IsMeasureValid == true here then its measure was
+            // handed by an ancestor and can be ignored. The measure may have also caused the
+            // control to be removed.
+            if (!control.IsMeasureValid && control.IsAttachedToVisualTree)
             {
-                control.Measure(control.PreviousMeasure.Value);
+                if (control is ILayoutRoot root)
+                {
+                    root.Measure(Size.Infinity);
+                }
+                else
+                {
+                    control.Measure(control.PreviousMeasure.Value);
+                }
             }
-
-            _toMeasure.Remove(control);
         }
 
         private void Arrange(ILayoutable control)
         {
-            var root = control as ILayoutRoot;
-            var parent = control.VisualParent as ILayoutable;
-
-            if (root != null)
-            {
-                root.Arrange(new Rect(root.DesiredSize));
-            }
-            else if (parent != null)
+            if (control.VisualParent is ILayoutable parent)
             {
                 Arrange(parent);
             }
 
-            if (control.PreviousArrange.HasValue)
+            if (!control.IsArrangeValid && control.IsAttachedToVisualTree)
             {
-                control.Arrange(control.PreviousArrange.Value);
+                if (control is ILayoutRoot root)
+                {
+                    root.Arrange(new Rect(control.DesiredSize));
+                }
+                else
+                {
+                    control.Arrange(control.PreviousArrange.Value);
+                }
             }
-
-            _toArrange.Remove(control);
         }
 
         private void QueueLayoutPass()

src/Avalonia.Layout/Layoutable.cs

@@ -378,8 +378,12 @@ namespace Avalonia.Layout
 
                 IsMeasureValid = false;
                 IsArrangeValid = false;
-                LayoutManager.Instance?.InvalidateMeasure(this);
-                InvalidateVisual();
+
+                if (((ILayoutable)this).IsAttachedToVisualTree)
+                {
+                    LayoutManager.Instance?.InvalidateMeasure(this);
+                    InvalidateVisual();
+                }
             }
         }
 
@@ -393,8 +397,12 @@ namespace Avalonia.Layout
                 Logger.Verbose(LogArea.Layout, this, "Invalidated arrange");
 
                 IsArrangeValid = false;
-                LayoutManager.Instance?.InvalidateArrange(this);
-                InvalidateVisual();
+
+                if (((ILayoutable)this).IsAttachedToVisualTree)
+                {
+                    LayoutManager.Instance?.InvalidateArrange(this);
+                    InvalidateVisual();
+                }
             }
         }
 
@@ -612,7 +620,7 @@ namespace Avalonia.Layout
         /// <inheritdoc/>
         protected override sealed void OnVisualParentChanged(IVisual oldParent, IVisual newParent)
         {
-            foreach (ILayoutable i in this.GetSelfAndVisualDescendents())
+            foreach (ILayoutable i in this.GetSelfAndVisualDescendants())
             {
                 i.InvalidateMeasure();
             }

src/Avalonia.Styling/LogicalTree/ILogical.cs

@@ -36,6 +36,16 @@ namespace Avalonia.LogicalTree
         /// </summary>
         IAvaloniaReadOnlyList<ILogical> LogicalChildren { get; }
 
+        /// <summary>
+        /// Notifies the control that it is being attached to a rooted logical tree.
+        /// </summary>
+        /// <param name="e">The event args.</param>
+        /// <remarks>
+        /// This method will be called automatically by the framework, you should not need to call
+        /// this method yourself.
+        /// </remarks>
+        void NotifyAttachedToLogicalTree(LogicalTreeAttachmentEventArgs e);
+
         /// <summary>
         /// Notifies the control that it is being detached from a rooted logical tree.
         /// </summary>

src/Avalonia.Styling/LogicalTree/LogicalExtensions.cs

@@ -37,15 +37,15 @@ namespace Avalonia.LogicalTree
             return logical.LogicalChildren;
         }
 
-        public static IEnumerable<ILogical> GetLogicalDescendents(this ILogical logical)
+        public static IEnumerable<ILogical> GetLogicalDescendants(this ILogical logical)
         {
             foreach (ILogical child in logical.LogicalChildren)
             {
                 yield return child;
 
-                foreach (ILogical descendent in child.GetLogicalDescendents())
+                foreach (ILogical descendant in child.GetLogicalDescendants())
                 {
-                    yield return descendent;
+                    yield return descendant;
                 }
             }
         }

src/Avalonia.Styling/Styling/DescendentSelector.cs

@@ -7,16 +7,16 @@ using Avalonia.LogicalTree;
 
 namespace Avalonia.Styling
 {
-    internal class DescendentSelector : Selector
+    internal class DescendantSelector : Selector
     {
         private readonly Selector _parent;
         private string _selectorString;
 
-        public DescendentSelector(Selector parent)
+        public DescendantSelector(Selector parent)
         {
             if (parent == null)
             {
-                throw new InvalidOperationException("Descendent selector must be preceeded by a selector.");
+                throw new InvalidOperationException("Descendant selector must be preceeded by a selector.");
             }
 
             _parent = parent;
@@ -41,7 +41,7 @@ namespace Avalonia.Styling
         protected override SelectorMatch Evaluate(IStyleable control, bool subscribe)
         {
             ILogical c = (ILogical)control;
-            List<IObservable<bool>> descendentMatches = new List<IObservable<bool>>();
+            List<IObservable<bool>> descendantMatches = new List<IObservable<bool>>();
 
             while (c != null)
             {
@@ -60,14 +60,14 @@ namespace Avalonia.Styling
                     }
                     else
                     {
-                        descendentMatches.Add(match.ObservableResult);
+                        descendantMatches.Add(match.ObservableResult);
                     }
                 }
             }
 
-            if (descendentMatches.Count > 0)
+            if (descendantMatches.Count > 0)
             {
-                return new SelectorMatch(StyleActivator.Or(descendentMatches));
+                return new SelectorMatch(StyleActivator.Or(descendantMatches));
             }
             else
             {

src/Avalonia.Styling/Styling/Selectors.cs

@@ -42,13 +42,13 @@ namespace Avalonia.Styling
         }
 
         /// <summary>
-        /// Returns a selector which matches a descendent of a previous selector.
+        /// Returns a selector which matches a descendant of a previous selector.
         /// </summary>
         /// <param name="previous">The previous selector.</param>
         /// <returns>The selector.</returns>
-        public static Selector Descendent(this Selector previous)
+        public static Selector Descendant(this Selector previous)
         {
-            return new DescendentSelector(previous);
+            return new DescendantSelector(previous);
         }
 
         /// <summary>

src/Avalonia.Visuals/Platform/ILockedFramebuffer.cs

@@ -27,7 +27,7 @@ namespace Avalonia.Platform
         /// <summary>
         /// DPI of underling screen
         /// </summary>
-        Size Dpi { get; }
+        Vector Dpi { get; }
         
         /// <summary>
         /// Pixel format

src/Avalonia.Visuals/Rendering/ImmediateRenderer.cs

@@ -164,7 +164,7 @@ namespace Avalonia.Rendering
 
         private static void ClearTransformedBounds(IVisual visual)
         {
-            foreach (var e in visual.GetSelfAndVisualDescendents())
+            foreach (var e in visual.GetSelfAndVisualDescendants())
             {
                 BoundsTracker.SetTransformedBounds((Visual)visual, null);
             }

src/Avalonia.Visuals/Vector.cs

@@ -52,8 +52,6 @@ namespace Avalonia
             return new Point(a._x, a._y);
         }
 
-        
-
         /// <summary>
         /// Calculates the dot product of two vectors
         /// </summary>
@@ -65,6 +63,17 @@ namespace Avalonia
             return a.X*b.X + a.Y*b.Y;
         }
 
+        /// <summary>
+        /// Scales a vector.
+        /// </summary>
+        /// <param name="vector">The vector</param>
+        /// <param name="scale">The scaling factor.</param>
+        /// <returns>The scaled vector.</returns>
+        public static Vector operator *(Vector vector, double scale)
+        {
+            return new Vector(vector._x * scale, vector._y * scale);
+        }
+
         /// <summary>
         /// Length of the vector
         /// </summary>

src/Avalonia.Visuals/Visual.cs

@@ -314,7 +314,7 @@ namespace Avalonia
 
         /// <summary>
         /// Calls the <see cref="OnAttachedToVisualTree(VisualTreeAttachmentEventArgs)"/> method 
-        /// for this control and all of its visual descendents.
+        /// for this control and all of its visual descendants.
         /// </summary>
         /// <param name="e">The event args.</param>
         protected virtual void OnAttachedToVisualTreeCore(VisualTreeAttachmentEventArgs e)
@@ -342,7 +342,7 @@ namespace Avalonia
 
         /// <summary>
         /// Calls the <see cref="OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs)"/> method 
-        /// for this control and all of its visual descendents.
+        /// for this control and all of its visual descendants.
         /// </summary>
         /// <param name="e">The event args.</param>
         protected virtual void OnDetachedFromVisualTreeCore(VisualTreeAttachmentEventArgs e)
@@ -422,7 +422,7 @@ namespace Avalonia
 
                 if (visual == null)
                 {
-                    throw new ArgumentException("'visual' is not a descendent of 'ancestor'.");
+                    throw new ArgumentException("'visual' is not a descendant of 'ancestor'.");
                 }
             }
 

src/Avalonia.Visuals/VisualTree/VisualExtensions.cs

@@ -123,33 +123,33 @@ namespace Avalonia.VisualTree
         }
 
         /// <summary>
-        /// Enumerates the descendents of an <see cref="IVisual"/> in the visual tree.
+        /// Enumerates the descendants of an <see cref="IVisual"/> in the visual tree.
         /// </summary>
         /// <param name="visual">The visual.</param>
         /// <returns>The visual's ancestors.</returns>
-        public static IEnumerable<IVisual> GetVisualDescendents(this IVisual visual)
+        public static IEnumerable<IVisual> GetVisualDescendants(this IVisual visual)
         {
             foreach (IVisual child in visual.VisualChildren)
             {
                 yield return child;
 
-                foreach (IVisual descendent in child.GetVisualDescendents())
+                foreach (IVisual descendant in child.GetVisualDescendants())
                 {
-                    yield return descendent;
+                    yield return descendant;
                 }
             }
         }
 
         /// <summary>
-        /// Enumerates an <see cref="IVisual"/> and its descendents in the visual tree.
+        /// Enumerates an <see cref="IVisual"/> and its descendants in the visual tree.
         /// </summary>
         /// <param name="visual">The visual.</param>
         /// <returns>The visual and its ancestors.</returns>
-        public static IEnumerable<IVisual> GetSelfAndVisualDescendents(this IVisual visual)
+        public static IEnumerable<IVisual> GetSelfAndVisualDescendants(this IVisual visual)
         {
             yield return visual;
 
-            foreach (var ancestor in visual.GetVisualDescendents())
+            foreach (var ancestor in visual.GetVisualDescendants())
             {
                 yield return ancestor;
             }
@@ -196,7 +196,7 @@ namespace Avalonia.VisualTree
         /// Tests whether an <see cref="IVisual"/> is an ancestor of another visual.
         /// </summary>
         /// <param name="visual">The visual.</param>
-        /// <param name="target">The potential descendent.</param>
+        /// <param name="target">The potential descendant.</param>
         /// <returns>
         /// True if <paramref name="visual"/> is an ancestor of <paramref name="target"/>;
         /// otherwise false.

src/Gtk/Avalonia.Gtk/GtkPlatform.cs

@@ -51,7 +51,6 @@ namespace Avalonia.Gtk
                 .Bind<IClipboard>().ToSingleton<ClipboardImpl>()
                 .Bind<IStandardCursorFactory>().ToConstant(CursorFactory.Instance)
                 .Bind<IKeyboardDevice>().ToConstant(GtkKeyboardDevice.Instance)
-                .Bind<IMouseDevice>().ToConstant(GtkMouseDevice.Instance)
                 .Bind<IPlatformSettings>().ToConstant(s_instance)
                 .Bind<IPlatformThreadingInterface>().ToConstant(s_instance)
                 .Bind<IRendererFactory>().ToConstant(s_instance)

src/Gtk/Avalonia.Gtk/SurfaceFramebuffer.cs

@@ -48,7 +48,7 @@ namespace Avalonia.Gtk
         public int Height => _surface.Height;
         public int RowBytes => _surface.Stride;
         //TODO: Proper DPI detect
-        public Size Dpi => new Size(96, 96);
+        public Vector Dpi => new Vector(96, 96);
         public PixelFormat Format => PixelFormat.Bgra8888;
     }
 }

src/Gtk/Avalonia.Gtk/TopLevelImpl.cs

@@ -75,6 +75,8 @@ namespace Avalonia.Gtk
             }
         }
 
+        public IMouseDevice MouseDevice => GtkMouseDevice.Instance;
+
         public Avalonia.Controls.WindowState WindowState
         {
             get
@@ -114,6 +116,7 @@ namespace Avalonia.Gtk
 
         public Action Closed { get; set; }
 
+
         public Action Deactivated { get; set; }
 
         public Action<RawInputEventArgs> Input { get; set; }

src/Gtk/Avalonia.Gtk3/Gtk3Platform.cs

@@ -34,7 +34,6 @@ namespace Avalonia.Gtk3
                 .Bind<IClipboard>().ToSingleton<ClipboardImpl>()
                 .Bind<IStandardCursorFactory>().ToConstant(new CursorFactory())
                 .Bind<IKeyboardDevice>().ToConstant(Keyboard)
-                .Bind<IMouseDevice>().ToConstant(Mouse)
                 .Bind<IPlatformSettings>().ToConstant(Instance)
                 .Bind<IPlatformThreadingInterface>().ToConstant(Instance)
                 .Bind<ISystemDialogImpl>().ToSingleton<SystemDialog>()

src/Gtk/Avalonia.Gtk3/ImageSurfaceFramebuffer.cs

@@ -52,12 +52,11 @@ namespace Avalonia.Gtk3
         public int RowBytes { get; }
 
         
-        public Size Dpi
+        public Vector Dpi
         {
             get
             {
-                
-                return new Size(96, 96) * _factor;
+                return new Vector(96, 96) * _factor;
             }
         }
 

src/Gtk/Avalonia.Gtk3/Interop/GObject.cs

@@ -41,7 +41,7 @@ namespace Avalonia.Gtk3.Interop
 
     class GtkWindow : GtkWidget
     {
-        
+        public static GtkWindow Null { get; } = new GtkWindow();
     }
 
     class GtkImContext : GObject

src/Gtk/Avalonia.Gtk3/Interop/Utf8Buffer.cs

@@ -11,6 +11,8 @@ namespace Avalonia.Gtk3.Interop
             
         public Utf8Buffer(string s) : base(IntPtr.Zero, true)
         {
+            if (s == null)
+                return;
             _data = Encoding.UTF8.GetBytes(s);
             _gchandle = GCHandle.Alloc(_data, GCHandleType.Pinned);
             handle = _gchandle.AddrOfPinnedObject();

src/Gtk/Avalonia.Gtk3/SystemDialogs.cs

@@ -18,7 +18,8 @@ namespace Avalonia.Gtk3
             bool multiselect, string initialFileName)
         {
             GtkFileChooser dlg;
-            using (var name = title != null ? new Utf8Buffer(title) : null)
+            parent = parent ?? GtkWindow.Null;
+            using (var name = new Utf8Buffer(title))
                 dlg = Native.GtkFileChooserDialogNew(name, parent, action, IntPtr.Zero);
             if (multiselect)
                 Native.GtkFileChooserSetSelectMultiple(dlg, true);

src/Gtk/Avalonia.Gtk3/WindowBaseImpl.cs

@@ -233,6 +233,7 @@ namespace Avalonia.Gtk3
             }
         }
 
+        public IMouseDevice MouseDevice => Gtk3Platform.Mouse;
 
         public double Scaling => (double) 1 / (Native.GtkWidgetGetScaleFactor?.Invoke(GtkWidget) ?? 1);
 

src/Linux/Avalonia.LinuxFramebuffer/FramebufferToplevelImpl.cs

@@ -56,6 +56,7 @@ namespace Avalonia.LinuxFramebuffer
         }
 
         public Size ClientSize => _fb.PixelSize;
+        public IMouseDevice MouseDevice => LinuxFramebufferPlatform.MouseDevice;
         public double Scaling => 1;
         public IEnumerable<object> Surfaces => new object[] {_fb};
         public Action<RawInputEventArgs> Input { get; set; }

src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebuffer.cs

@@ -13,16 +13,16 @@ namespace Avalonia.LinuxFramebuffer
 {
     public sealed unsafe class LinuxFramebuffer : IFramebufferPlatformSurface, IDisposable
     {
-        private readonly Size _dpi;
+        private readonly Vector _dpi;
         private int _fd;
         private fb_fix_screeninfo _fixedInfo;
         private fb_var_screeninfo _varInfo;
         private IntPtr _mappedLength;
         private IntPtr _mappedAddress;
 
-        public LinuxFramebuffer(string fileName = null, Size? dpi = null)
+        public LinuxFramebuffer(string fileName = null, Vector? dpi = null)
         {
-            _dpi = dpi ?? new Size(96, 96);
+            _dpi = dpi ?? new Vector(96, 96);
             fileName = fileName ?? Environment.GetEnvironmentVariable("FRAMEBUFFER") ?? "/dev/fb0";
             _fd = NativeUnsafeMethods.open(fileName, 2, 0);
             if (_fd <= 0)

src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebufferPlatform.cs

@@ -33,7 +33,6 @@ namespace Avalonia.LinuxFramebuffer
             AvaloniaLocator.CurrentMutable
                 .Bind<IStandardCursorFactory>().ToTransient<CursorFactoryStub>()
                 .Bind<IKeyboardDevice>().ToConstant(KeyboardDevice)
-                .Bind<IMouseDevice>().ToConstant(MouseDevice)
                 .Bind<IPlatformSettings>().ToSingleton<PlatformSettings>()
                 .Bind<IRendererFactory>().ToConstant(ImmediateRenderer.Factory)
                 .Bind<IPlatformThreadingInterface>().ToConstant(PlatformThreadingInterface.Instance)

src/Linux/Avalonia.LinuxFramebuffer/LockedFramebuffer.cs

@@ -11,7 +11,7 @@ namespace Avalonia.LinuxFramebuffer
         private fb_var_screeninfo _varInfo;
         private readonly IntPtr _address;
 
-        public LockedFramebuffer(int fb, fb_fix_screeninfo fixedInfo, fb_var_screeninfo varInfo, IntPtr address, Size dpi)
+        public LockedFramebuffer(int fb, fb_fix_screeninfo fixedInfo, fb_var_screeninfo varInfo, IntPtr address, Vector dpi)
         {
             _fb = fb;
             _fixedInfo = fixedInfo;
@@ -41,7 +41,7 @@ namespace Avalonia.LinuxFramebuffer
         public int Width => (int)_varInfo.xres;
         public int Height => (int) _varInfo.yres;
         public int RowBytes => (int) _fixedInfo.line_length;
-        public Size Dpi { get; }
+        public Vector Dpi { get; }
         public PixelFormat Format => _varInfo.blue.offset == 16 ? PixelFormat.Rgba8888 : PixelFormat.Bgra8888;
     }
 }

src/Markup/Avalonia.Markup.Xaml/Data/MultiBinding.cs

@@ -102,7 +102,7 @@ namespace Avalonia.Markup.Xaml.Data
 
         private object ConvertValue(IList<object> values, Type targetType)
         {
-            var converted = Converter.Convert(values, targetType, null, CultureInfo.CurrentUICulture);
+            var converted = Converter.Convert(values, targetType, null, CultureInfo.CurrentCulture);
 
             if (converted == AvaloniaProperty.UnsetValue && FallbackValue != null)
             {

src/Markup/Avalonia.Markup.Xaml/Parsers/SelectorGrammar.cs

@@ -93,9 +93,9 @@ namespace Avalonia.Markup.Xaml.Parsers
 
         public static readonly Parser<ChildSyntax> Child = Parse.Char('>').Token().Return(new ChildSyntax());
 
-        public static readonly Parser<DescendentSyntax> Descendent =
+        public static readonly Parser<DescendantSyntax> Descendant =
             from child in Parse.WhiteSpace.Many()
-            select new DescendentSyntax();
+            select new DescendantSyntax();
 
         public static readonly Parser<TemplateSyntax> Template =
             from template in Parse.String("/template/").Token()
@@ -115,7 +115,7 @@ namespace Avalonia.Markup.Xaml.Parsers
             .Or<ISyntax>(Property)
             .Or<ISyntax>(Child)
             .Or<ISyntax>(Template)
-            .Or<ISyntax>(Descendent);
+            .Or<ISyntax>(Descendant);
 
         public static readonly Parser<IEnumerable<ISyntax>> Selector = SingleSelector.Many().End();
         
@@ -191,11 +191,11 @@ namespace Avalonia.Markup.Xaml.Parsers
             }
         }
 
-        public class DescendentSyntax : ISyntax
+        public class DescendantSyntax : ISyntax
         {
             public override bool Equals(object obj)
             {
-                return obj is DescendentSyntax;
+                return obj is DescendantSyntax;
             }
         }
 

src/Markup/Avalonia.Markup.Xaml/Parsers/SelectorParser.cs

@@ -47,7 +47,7 @@ namespace Avalonia.Markup.Xaml.Parsers
                 var name = i as SelectorGrammar.NameSyntax;
                 var property = i as SelectorGrammar.PropertySyntax;
                 var child = i as SelectorGrammar.ChildSyntax;
-                var descendent = i as SelectorGrammar.DescendentSyntax;
+                var descendant = i as SelectorGrammar.DescendantSyntax;
                 var template = i as SelectorGrammar.TemplateSyntax;
 
                 if (ofType != null)
@@ -102,9 +102,9 @@ namespace Avalonia.Markup.Xaml.Parsers
                 {
                     result = result.Child();
                 }
-                else if (descendent != null)
+                else if (descendant != null)
                 {
-                    result = result.Descendent();
+                    result = result.Descendant();
                 }
                 else if (template != null)
                 {

src/Markup/Avalonia.Markup/Data/BindingExpression.cs

@@ -122,7 +122,7 @@ namespace Avalonia.Markup.Data
                         value,
                         type,
                         ConverterParameter,
-                        CultureInfo.CurrentUICulture);
+                        CultureInfo.CurrentCulture);
 
                     if (converted == AvaloniaProperty.UnsetValue)
                     {
@@ -186,7 +186,7 @@ namespace Avalonia.Markup.Data
                     value,
                     _targetType,
                     ConverterParameter,
-                    CultureInfo.CurrentUICulture);
+                    CultureInfo.CurrentCulture);
 
                 notification = converted as BindingNotification;
 

src/Skia/Avalonia.Skia/BitmapImpl.cs

@@ -131,7 +131,7 @@ namespace Avalonia.Skia
             public int Width => _bmp.Width;
             public int Height => _bmp.Height;
             public int RowBytes => _bmp.RowBytes;
-            public Size Dpi { get; } = new Size(96, 96);
+            public Vector Dpi { get; } = new Vector(96, 96);
             public PixelFormat Format => _bmp.ColorType.ToPixelFormat();
         }
 

src/Skia/Avalonia.Skia/FramebufferRenderTarget.cs

@@ -76,7 +76,7 @@ namespace Avalonia.Skia
             canvas.RestoreToCount(0);
             canvas.Save();
             canvas.ResetMatrix();
-            var scale = Matrix.CreateScale(fb.Dpi.Width / 96, fb.Dpi.Height / 96);
+            var scale = Matrix.CreateScale(fb.Dpi.X / 96, fb.Dpi.Y / 96);
             return new DrawingContextImpl(canvas, visualBrushRenderer, scale, canvas, surface, shim, fb);
         }
     }

src/Windows/Avalonia.Direct2D1/Avalonia.Direct2D1.csproj

@@ -50,7 +50,9 @@
     </Compile>
     <Compile Include="Direct2D1Platform.cs" />
     <Compile Include="Disposable.cs" />
+    <Compile Include="ExternalRenderTarget.cs" />
     <Compile Include="HwndRenderTarget.cs" />
+    <Compile Include="IExternalDirect2DRenderTargetSurface.cs" />
     <Compile Include="Media\BrushImpl.cs" />
     <Compile Include="Media\BrushWrapper.cs" />
     <Compile Include="Media\DrawingContextImpl.cs" />

src/Windows/Avalonia.Direct2D1/Direct2D1Platform.cs

@@ -135,12 +135,17 @@ namespace Avalonia.Direct2D1
 
         public IRenderTarget CreateRenderTarget(IEnumerable<object> surfaces)
         {
-            var nativeWindow = surfaces?.OfType<IPlatformHandle>().FirstOrDefault();
-            if (nativeWindow != null)
+            foreach (var s in surfaces)
             {
-                if(nativeWindow.HandleDescriptor != "HWND")
-                    throw new NotSupportedException("Don't know how to create a Direct2D1 renderer from " + nativeWindow.HandleDescriptor);
-                return new HwndRenderTarget(nativeWindow);
+                if (s is IPlatformHandle nativeWindow)
+                {
+                    if (nativeWindow.HandleDescriptor != "HWND")
+                        throw new NotSupportedException("Don't know how to create a Direct2D1 renderer from " +
+                                                        nativeWindow.HandleDescriptor);
+                    return new HwndRenderTarget(nativeWindow);
+                }
+                if (s is IExternalDirect2DRenderTargetSurface external)
+                    return new ExternalRenderTarget(external, s_dwfactory);
             }
             throw new NotSupportedException("Don't know how to create a Direct2D1 renderer from any of provided surfaces");
         }

src/Windows/Avalonia.Direct2D1/ExternalRenderTarget.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Avalonia.Direct2D1.Media;
+using Avalonia.Platform;
+using Avalonia.Rendering;
+using SharpDX;
+using DirectWriteFactory = SharpDX.DirectWrite.Factory;
+
+namespace Avalonia.Direct2D1
+{
+    class ExternalRenderTarget : IRenderTarget
+    {
+        private readonly IExternalDirect2DRenderTargetSurface _externalRenderTargetProvider;
+        private readonly DirectWriteFactory _dwFactory;
+        private SharpDX.Direct2D1.RenderTarget _target;
+        public ExternalRenderTarget(IExternalDirect2DRenderTargetSurface externalRenderTargetProvider,
+            DirectWriteFactory dwFactory)
+        {
+            _externalRenderTargetProvider = externalRenderTargetProvider;
+            _dwFactory = dwFactory;
+        }
+
+        public void Dispose()
+        {
+            _target?.Dispose();
+            _target = null;
+        }
+
+        public IDrawingContextImpl CreateDrawingContext(IVisualBrushRenderer visualBrushRenderer)
+        {
+            _target = _target ?? _externalRenderTargetProvider.CreateRenderTarget();
+            _externalRenderTargetProvider.BeforeDrawing();
+            return new DrawingContextImpl(visualBrushRenderer, _target, _dwFactory, null, () =>
+            {
+                try
+                {
+                    _externalRenderTargetProvider.AfterDrawing();
+                }
+                catch (SharpDXException ex) when ((uint) ex.HResult == 0x8899000C) // D2DERR_RECREATE_TARGET
+                {
+                    _target?.Dispose();
+                    _target = null;
+                }
+            });
+        }
+    }
+}

src/Windows/Avalonia.Direct2D1/IExternalDirect2DRenderTargetSurface.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Avalonia.Direct2D1
+{
+    public interface IExternalDirect2DRenderTargetSurface
+    {
+        SharpDX.Direct2D1.RenderTarget CreateRenderTarget();
+        void BeforeDrawing();
+        void AfterDrawing();
+    }
+}

src/Windows/Avalonia.Direct2D1/Media/DrawingContextImpl.cs

@@ -23,6 +23,7 @@ namespace Avalonia.Direct2D1.Media
         private readonly IVisualBrushRenderer _visualBrushRenderer;
         private readonly SharpDX.Direct2D1.RenderTarget _renderTarget;
         private readonly SharpDX.DXGI.SwapChain1 _swapChain;
+        private readonly Action _finishedCallback;
         private SharpDX.DirectWrite.Factory _directWriteFactory;
 
         /// <summary>
@@ -32,15 +33,18 @@ namespace Avalonia.Direct2D1.Media
         /// <param name="renderTarget">The render target to draw to.</param>
         /// <param name="directWriteFactory">The DirectWrite factory.</param>
         /// <param name="swapChain">An optional swap chain associated with this drawing context.</param>
+        /// <param name="finishedCallback">An optional delegate to be called when context is disposed.</param>
         public DrawingContextImpl(
             IVisualBrushRenderer visualBrushRenderer,
             SharpDX.Direct2D1.RenderTarget renderTarget,
             SharpDX.DirectWrite.Factory directWriteFactory,
-            SharpDX.DXGI.SwapChain1 swapChain = null)
+            SharpDX.DXGI.SwapChain1 swapChain = null,
+            Action finishedCallback = null)
         {
             _visualBrushRenderer = visualBrushRenderer;
             _renderTarget = renderTarget;
             _swapChain = swapChain;
+            _finishedCallback = finishedCallback;
             _directWriteFactory = directWriteFactory;
             _swapChain = swapChain;
             _renderTarget.BeginDraw();
@@ -73,6 +77,7 @@ namespace Avalonia.Direct2D1.Media
                 _renderTarget.EndDraw();
 
                 _swapChain?.Present(1, SharpDX.DXGI.PresentFlags.None);
+                _finishedCallback?.Invoke();
             }
             catch (SharpDXException ex) when ((uint)ex.HResult == 0x8899000C) // D2DERR_RECREATE_TARGET
             {

src/Windows/Avalonia.Direct2D1/Media/Imaging/WritableWicBitmapImpl.cs

@@ -37,7 +37,7 @@ namespace Avalonia.Direct2D1.Media.Imaging
             public int Width => _lock.Size.Width;
             public int Height => _lock.Size.Height;
             public int RowBytes => _lock.Stride;
-            public Size Dpi { get; } = new Size(96, 96);
+            public Vector Dpi { get; } = new Vector(96, 96);
             public PixelFormat Format => _format;
 
         }

src/Windows/Avalonia.Win32/Input/WindowsMouseDevice.cs

@@ -10,7 +10,7 @@ namespace Avalonia.Win32.Input
 {
     class WindowsMouseDevice : MouseDevice
     {
-        public new static WindowsMouseDevice Instance { get; } = new WindowsMouseDevice();
+        public static WindowsMouseDevice Instance { get; } = new WindowsMouseDevice();
 
         public WindowImpl CurrentWindow
         {

src/Windows/Avalonia.Win32/Win32Platform.cs

@@ -66,7 +66,6 @@ namespace Avalonia.Win32
                 .Bind<IClipboard>().ToSingleton<ClipboardImpl>()
                 .Bind<IStandardCursorFactory>().ToConstant(CursorFactory.Instance)
                 .Bind<IKeyboardDevice>().ToConstant(WindowsKeyboardDevice.Instance)
-                .Bind<IMouseDevice>().ToConstant(WindowsMouseDevice.Instance)
                 .Bind<IPlatformSettings>().ToConstant(s_instance)
                 .Bind<IPlatformThreadingInterface>().ToConstant(s_instance)
                 .Bind<IRenderLoop>().ToConstant(new RenderLoop(60))

src/Windows/Avalonia.Win32/WindowFramebuffer.cs

@@ -39,7 +39,7 @@ namespace Avalonia.Win32
         public int RowBytes => Width * 4;
         public PixelFormat Format => PixelFormat.Bgra8888;
 
-        public Size Dpi
+        public Vector Dpi
         {
             get
             {
@@ -56,10 +56,10 @@ namespace Avalonia.Win32
                             out dpix,
                             out dpiy) == 0)
                     {
-                        return new Size(dpix, dpiy);
+                        return new Vector(dpix, dpiy);
                     }
                 }
-                return new Size(96, 96);
+                return new Vector(96, 96);
             }
         }
 

src/Windows/Avalonia.Win32/WindowImpl.cs

@@ -133,6 +133,8 @@ namespace Avalonia.Win32
             }
         }
 
+        public IMouseDevice MouseDevice => WindowsMouseDevice.Instance;
+
         public WindowState WindowState
         {
             get

src/iOS/Avalonia.iOS/EmulatedFramebuffer.cs

@@ -24,7 +24,7 @@ namespace Avalonia.iOS
             Width = (int) frame.Width * factor;
             Height = (int) frame.Height * factor;
             RowBytes = Width * 4;
-            Dpi = new Size(96, 96) * factor;
+            Dpi = new Vector(96, 96) * factor;
             Format = PixelFormat.Rgba8888;
             Address = Marshal.AllocHGlobal(Height * RowBytes);
         }
@@ -53,7 +53,7 @@ namespace Avalonia.iOS
         public int Width { get; }
         public int Height { get; }
         public int RowBytes { get; }
-        public Size Dpi { get; }
+        public Vector Dpi { get; }
         public PixelFormat Format { get; }
     }
 }

src/iOS/Avalonia.iOS/TopLevelImpl.cs

@@ -61,6 +61,8 @@ namespace Avalonia.iOS
 
         public Size ClientSize => Bounds.Size.ToAvalonia();
 
+        public IMouseDevice MouseDevice => iOSPlatform.MouseDevice;
+        
         public override void Draw(CGRect rect)
         {
             Paint?.Invoke(new Rect(rect.X, rect.Y, rect.Width, rect.Height));

src/iOS/Avalonia.iOS/iOSPlatform.cs

@@ -57,7 +57,6 @@ namespace Avalonia.iOS
                 //.Bind<ISystemDialogImpl>().ToTransient<SystemDialogImpl>()
                 .Bind<IStandardCursorFactory>().ToTransient<CursorFactory>()
                 .Bind<IKeyboardDevice>().ToConstant(KeyboardDevice)
-                .Bind<IMouseDevice>().ToConstant(MouseDevice)
                 .Bind<IRendererFactory>().ToConstant(ImmediateRenderer.Factory)
                 .Bind<IPlatformSettings>().ToSingleton<PlatformSettings>()
                 .Bind<IPlatformThreadingInterface>().ToConstant(PlatformThreadingInterface.Instance)

tests/Avalonia.Base.UnitTests/Avalonia.Base.UnitTests.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
   <PropertyGroup>
     <TargetFrameworks>net461;netcoreapp1.1</TargetFrameworks>
+    <OutputType>Library</OutputType>
   </PropertyGroup>
   <Import Project="..\..\build\UnitTests.NetCore.targets" />
   <Import Project="..\..\build\Moq.props" />

tests/Avalonia.Base.UnitTests/Collections/AvaloniaListExtenionsTests.cs

@@ -0,0 +1,134 @@
+using System;
+using System.Linq;
+using Avalonia.Collections;
+using Xunit;
+
+namespace Avalonia.Base.UnitTests.Collections
+{
+    public class AvaloniaListExtenionsTests
+    {
+        [Fact]
+        public void CreateDerivedList_Creates_Initial_Items()
+        {
+            var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+            var target = source.CreateDerivedList(x => new Wrapper(x));
+            var result = target.Select(x => x.Value).ToList();
+
+            Assert.Equal(source, result);
+        }
+
+        [Fact]
+        public void CreateDerivedList_Handles_Add()
+        {
+            var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+            var target = source.CreateDerivedList(x => new Wrapper(x));
+
+            source.Add(4);
+
+            var result = target.Select(x => x.Value).ToList();
+
+            Assert.Equal(source, result);
+        }
+
+        [Fact]
+        public void CreateDerivedList_Handles_Insert()
+        {
+            var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+            var target = source.CreateDerivedList(x => new Wrapper(x));
+
+            source.Insert(1, 4);
+
+            var result = target.Select(x => x.Value).ToList();
+
+            Assert.Equal(source, result);
+        }
+
+        [Fact]
+        public void CreateDerivedList_Handles_Remove()
+        {
+            var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+            var target = source.CreateDerivedList(x => new Wrapper(x));
+
+            source.Remove(2);
+
+            var result = target.Select(x => x.Value).ToList();
+
+            Assert.Equal(source, result);
+        }
+
+        [Fact]
+        public void CreateDerivedList_Handles_RemoveRange()
+        {
+            var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+            var target = source.CreateDerivedList(x => new Wrapper(x));
+
+            source.RemoveRange(1, 2);
+
+            var result = target.Select(x => x.Value).ToList();
+
+            Assert.Equal(source, result);
+        }
+
+        [Fact]
+        public void CreateDerivedList_Handles_Move()
+        {
+            var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+            var target = source.CreateDerivedList(x => new Wrapper(x));
+
+            source.Move(2, 0);
+
+            var result = target.Select(x => x.Value).ToList();
+
+            Assert.Equal(source, result);
+        }
+
+        [Fact]
+        public void CreateDerivedList_Handles_MoveRange()
+        {
+            var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+            var target = source.CreateDerivedList(x => new Wrapper(x));
+
+            source.MoveRange(1, 2, 0);
+
+            var result = target.Select(x => x.Value).ToList();
+
+            Assert.Equal(source, result);
+        }
+
+        [Fact]
+        public void CreateDerivedList_Handles_Replace()
+        {
+            var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+            var target = source.CreateDerivedList(x => new Wrapper(x));
+
+            source[1] = 4;
+
+            var result = target.Select(x => x.Value).ToList();
+
+            Assert.Equal(source, result);
+        }
+
+        [Fact]
+        public void CreateDerivedList_Handles_Clear()
+        {
+            var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+            var target = source.CreateDerivedList(x => new Wrapper(x));
+
+            source.Clear();
+
+            var result = target.Select(x => x.Value).ToList();
+
+            Assert.Equal(source, result);
+        }
+
+        private class Wrapper
+        {
+            public Wrapper(int value)
+            {
+                Value = value;
+            }
+
+            public int Value { get; }
+        }
+    }
+}

tests/Avalonia.Base.UnitTests/Properties/AssemblyInfo.cs

@@ -7,4 +7,4 @@ using Xunit;
 [assembly: AssemblyTitle("Avalonia.UnitTests")]
 
 // Don't run tests in parallel.
-[assembly: CollectionBehavior(DisableTestParallelization = true)]
+[assembly: CollectionBehavior(DisableTestParallelization = true)]

tests/Avalonia.Benchmarks/Avalonia.Benchmarks.csproj

@@ -49,6 +49,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Layout\Measure.cs" />
     <Compile Include="Styling\ApplyStyling.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
@@ -100,7 +101,7 @@
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.9.2" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.10.8" />
   </ItemGroup>
   <Import Project="$(MSBuildThisFileDirectory)..\..\src\Shared\nuget.workaround.targets" />
 </Project>

tests/Avalonia.Benchmarks/Layout/Measure.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using Avalonia.Controls;
+using Avalonia.Layout;
+using Avalonia.UnitTests;
+using BenchmarkDotNet.Attributes;
+
+namespace Avalonia.Benchmarks.Layout
+{
+    [MemoryDiagnoser]
+    public class Measure : IDisposable
+    {
+        private IDisposable _app;
+        private TestRoot root;
+        private List<Control> controls = new List<Control>();
+
+        public Measure()
+        {
+            _app = UnitTestApplication.Start(TestServices.RealLayoutManager);
+
+            var panel = new StackPanel();
+            root = new TestRoot { Child = panel };
+            controls.Add(panel);
+            CreateChildren(panel, 3, 5);
+            LayoutManager.Instance.ExecuteInitialLayoutPass(root);
+        }
+
+        public void Dispose()
+        {
+            _app.Dispose();
+        }
+
+        [Benchmark]
+        public void Remeasure_Half()
+        {
+            var random = new Random(1);
+
+            foreach (var control in controls)
+            {
+                if (random.Next(2) == 0)
+                {
+                    control.InvalidateMeasure();
+                }
+            }
+
+            LayoutManager.Instance.ExecuteLayoutPass();
+        }
+
+        private void CreateChildren(IPanel parent, int childCount, int iterations)
+        {
+            for (var i = 0; i < childCount; ++i)
+            {
+                var control = new StackPanel();
+                parent.Children.Add(control);
+
+                if (iterations > 0)
+                {
+                    CreateChildren(control, childCount, iterations - 1);
+                }
+
+                controls.Add(control);
+            }
+        }
+    }
+}

tests/Avalonia.Benchmarks/Styling/ApplyStyling.cs

@@ -11,6 +11,7 @@ using Avalonia.VisualTree;
 
 namespace Avalonia.Benchmarks.Styling
 {
+    [MemoryDiagnoser]
     public class ApplyStyling : IDisposable
     {
         private IDisposable _app;

tests/Avalonia.Controls.UnitTests/Avalonia.Controls.UnitTests.csproj

@@ -1,12 +1,16 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
   <PropertyGroup>
     <TargetFrameworks>net461;netcoreapp1.1</TargetFrameworks>
+    <OutputType>Library</OutputType>
   </PropertyGroup>
   <Import Project="..\..\build\UnitTests.NetCore.targets" />
   <Import Project="..\..\build\Moq.props" />
   <Import Project="..\..\build\XUnit.props" />
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\Microsoft.Reactive.Testing.props" />
+  <ItemGroup>
+    <PackageReference Include="System.ValueTuple" Version="4.3.1" />
+  </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\Markup\Avalonia.Markup.Xaml\Avalonia.Markup.Xaml.csproj" />
     <ProjectReference Include="..\..\src\Markup\Avalonia.Markup\Avalonia.Markup.csproj" />

tests/Avalonia.Controls.UnitTests/ListBoxTests.cs

@@ -245,7 +245,7 @@ namespace Avalonia.Controls.UnitTests
 
             // The items were created before the template was applied, so now we need to go back
             // and re-arrange everything.
-            foreach (IControl i in target.GetSelfAndVisualDescendents())
+            foreach (IControl i in target.GetSelfAndVisualDescendants())
             {
                 i.InvalidateMeasure();
             }

tests/Avalonia.Controls.UnitTests/Presenters/ContentPresenterTests_InTemplate.cs

@@ -0,0 +1,291 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System.Linq;
+using Avalonia.Controls.Presenters;
+using Avalonia.Controls.Templates;
+using Avalonia.LogicalTree;
+using Avalonia.UnitTests;
+using Avalonia.VisualTree;
+using Moq;
+using Xunit;
+
+namespace Avalonia.Controls.UnitTests.Presenters
+{
+    /// <summary>
+    /// Tests for ContentControls that are hosted in a control template.
+    /// </summary>
+    public class ContentPresenterTests_InTemplate
+    {
+        [Fact]
+        public void Should_Register_With_Host_When_TemplatedParent_Set()
+        {
+            var host = new Mock<IContentPresenterHost>();
+            var target = new ContentPresenter();
+
+            target.SetValue(Control.TemplatedParentProperty, host.Object);
+
+            host.Verify(x => x.RegisterContentPresenter(target));
+        }
+
+        [Fact]
+        public void Setting_Content_To_Control_Should_Set_Child()
+        {
+            var (target, _) = CreateTarget();
+            var child = new Border();
+
+            target.Content = child;
+
+            Assert.Equal(child, target.Child);
+        }
+
+        [Fact]
+        public void Setting_Content_To_Control_Should_Update_Logical_Tree()
+        {
+            var (target, parent) = CreateTarget();
+            var child = new Border();
+
+            target.Content = child;
+
+            Assert.Equal(parent, child.GetLogicalParent());
+            Assert.Equal(new[] { child }, parent.GetLogicalChildren());
+        }
+
+        [Fact]
+        public void Setting_Content_To_Control_Should_Update_Visual_Tree()
+        {
+            var (target, _) = CreateTarget();
+            var child = new Border();
+
+            target.Content = child;
+
+            Assert.Equal(target, child.GetVisualParent());
+            Assert.Equal(new[] { child }, target.GetVisualChildren());
+        }
+
+        [Fact]
+        public void Setting_Content_To_String_Should_Create_TextBlock()
+        {
+            var (target, _) = CreateTarget();
+
+            target.Content = "Foo";
+
+            Assert.IsType<TextBlock>(target.Child);
+            Assert.Equal("Foo", ((TextBlock)target.Child).Text);
+        }
+
+        [Fact]
+        public void Setting_Content_To_String_Should_Update_Logical_Tree()
+        {
+            var (target, parent) = CreateTarget();
+
+            target.Content = "Foo";
+
+            var child = target.Child;
+            Assert.Equal(parent, child.GetLogicalParent());
+            Assert.Equal(new[] { child }, parent.GetLogicalChildren());
+        }
+
+        [Fact]
+        public void Setting_Content_To_String_Should_Update_Visual_Tree()
+        {
+            var (target, _) = CreateTarget();
+
+            target.Content = "Foo";
+
+            var child = target.Child;
+            Assert.Equal(target, child.GetVisualParent());
+            Assert.Equal(new[] { child }, target.GetVisualChildren());
+        }
+
+        [Fact]
+        public void Clearing_Control_Content_Should_Update_Logical_Tree()
+        {
+            var (target, _) = CreateTarget();
+            var child = new Border();
+
+            target.Content = child;
+            target.Content = null;
+
+            Assert.Equal(null, child.GetLogicalParent());
+            Assert.Empty(target.GetLogicalChildren());
+        }
+
+        [Fact]
+        public void Clearing_Control_Content_Should_Update_Visual_Tree()
+        {
+            var (target, _) = CreateTarget();
+            var child = new Border();
+
+            target.Content = child;
+            target.Content = null;
+
+            Assert.Equal(null, child.GetVisualParent());
+            Assert.Empty(target.GetVisualChildren());
+        }
+
+        [Fact]
+        public void Control_Content_Should_Not_Be_NameScope()
+        {
+            var (target, _) = CreateTarget();
+
+            target.Content = new TextBlock();
+
+            Assert.IsType<TextBlock>(target.Child);
+            Assert.Null(NameScope.GetNameScope((Control)target.Child));
+        }
+
+        [Fact]
+        public void DataTemplate_Created_Control_Should_Be_NameScope()
+        {
+            var (target, _) = CreateTarget();
+
+            target.Content = "Foo";
+
+            Assert.IsType<TextBlock>(target.Child);
+            Assert.NotNull(NameScope.GetNameScope((Control)target.Child));
+        }
+
+        [Fact]
+        public void Assigning_Control_To_Content_Should_Not_Set_DataContext()
+        {
+            var (target, _) = CreateTarget();
+            target.Content = new Border();
+
+            Assert.False(target.IsSet(Control.DataContextProperty));
+        }
+
+        [Fact]
+        public void Assigning_NonControl_To_Content_Should_Set_DataContext_On_UpdateChild()
+        {
+            var (target, _) = CreateTarget();
+            target.Content = "foo";
+
+            Assert.Equal("foo", target.DataContext);
+        }
+
+        [Fact]
+        public void Should_Use_ContentTemplate_If_Specified()
+        {
+            var (target, _) = CreateTarget();
+
+            target.ContentTemplate = new FuncDataTemplate<string>(_ => new Canvas());
+            target.Content = "Foo";
+
+            Assert.IsType<Canvas>(target.Child);
+        }
+
+        [Fact]
+        public void Should_Update_If_ContentTemplate_Changed()
+        {
+            var (target, _) = CreateTarget();
+
+            target.Content = "Foo";
+            Assert.IsType<TextBlock>(target.Child);
+
+            target.ContentTemplate = new FuncDataTemplate<string>(_ => new Canvas());
+            Assert.IsType<Canvas>(target.Child);
+
+            target.ContentTemplate = null;
+            Assert.IsType<TextBlock>(target.Child);
+        }
+
+        [Fact]
+        public void Assigning_Control_To_Content_After_NonControl_Should_Clear_DataContext()
+        {
+            var (target, _) = CreateTarget();
+
+            target.Content = "foo";
+
+            Assert.True(target.IsSet(Control.DataContextProperty));
+
+            target.Content = new Border();
+
+            Assert.False(target.IsSet(Control.DataContextProperty));
+        }
+
+        [Fact]
+        public void Recycles_DataTemplate()
+        {
+            var (target, _) = CreateTarget();
+            target.DataTemplates.Add(new FuncDataTemplate<string>(_ => new Border(), true));
+
+            target.Content = "foo";
+
+            var control = target.Child;
+            Assert.IsType<Border>(control);
+
+            target.Content = "bar";
+            Assert.Same(control, target.Child);
+        }
+
+        [Fact]
+        public void Detects_DataTemplate_Doesnt_Match_And_Doesnt_Recycle()
+        {
+            var (target, _) = CreateTarget();
+            target.DataTemplates.Add(new FuncDataTemplate<string>(x => x == "foo", _ => new Border(), true));
+
+            target.Content = "foo";
+
+            var control = target.Child;
+            Assert.IsType<Border>(control);
+
+            target.Content = "bar";
+            Assert.IsType<TextBlock>(target.Child);
+        }
+
+        [Fact]
+        public void Detects_DataTemplate_Doesnt_Support_Recycling()
+        {
+            var (target, _) = CreateTarget();
+            target.DataTemplates.Add(new FuncDataTemplate<string>(_ => new Border(), false));
+
+            target.Content = "foo";
+
+            var control = target.Child;
+            Assert.IsType<Border>(control);
+
+            target.Content = "bar";
+            Assert.NotSame(control, target.Child);
+        }
+
+        [Fact]
+        public void Reevaluates_DataTemplates_When_Recycling()
+        {
+            var (target, _) = CreateTarget();
+
+            target.DataTemplates.Add(new FuncDataTemplate<string>(x => x == "bar", _ => new Canvas(), true));
+            target.DataTemplates.Add(new FuncDataTemplate<string>(_ => new Border(), true));
+
+            target.Content = "foo";
+
+            var control = target.Child;
+            Assert.IsType<Border>(control);
+
+            target.Content = "bar";
+            Assert.IsType<Canvas>(target.Child);
+        }
+
+        (ContentPresenter presenter, ContentControl templatedParent) CreateTarget()
+        {
+            var templatedParent = new ContentControl
+            {
+                Template = new FuncControlTemplate<ContentControl>(x => 
+                    new ContentPresenter
+                    {
+                        Name = "PART_ContentPresenter",
+                    }),
+            };
+            var root = new TestRoot { Child = templatedParent };
+
+            templatedParent.ApplyTemplate();
+
+            return ((ContentPresenter)templatedParent.Presenter, templatedParent);
+        }
+
+        private class TestContentControl : ContentControl
+        {
+            public IControl Child { get; set; }
+        }
+    }
+}