diff --git a/build/Microsoft.Reactive.Testing.props b/build/Microsoft.Reactive.Testing.props
index 777bc4bb53..a0ba2163bb 100644
--- a/build/Microsoft.Reactive.Testing.props
+++ b/build/Microsoft.Reactive.Testing.props
@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="Microsoft.Reactive.Testing" Version="4.0.0" />
+    <PackageReference Include="Microsoft.Reactive.Testing" Version="4.1.6" />
   </ItemGroup>
 </Project>
diff --git a/build/ReactiveUI.props b/build/ReactiveUI.props
index 1208be34b8..f827cb9a32 100644
--- a/build/ReactiveUI.props
+++ b/build/ReactiveUI.props
@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="reactiveui" Version="9.0.1" />
+    <PackageReference Include="ReactiveUI" Version="10.3.6" />
   </ItemGroup>
 </Project>
diff --git a/build/Rx.props b/build/Rx.props
index 359ce53a92..edff0af160 100644
--- a/build/Rx.props
+++ b/build/Rx.props
@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="System.Reactive" Version="4.0.0" />
+    <PackageReference Include="System.Reactive" Version="4.1.6" />
   </ItemGroup>
 </Project>
diff --git a/dirs.proj b/dirs.proj
index e56320e73f..4b3b1183f0 100644
--- a/dirs.proj
+++ b/dirs.proj
@@ -8,7 +8,8 @@
     <ProjectReference Remove="src/Markup/Avalonia.Markup.Xaml/PortableXaml/**/*.*proj" />
     <ProjectReference Remove="src/Markup/Avalonia.Markup.Xaml/XamlIl/**/*.*proj" />
   </ItemGroup>
-  <ItemGroup Condition="!Exists('$(MSBuildExtensionsPath)\Xamarin\Android')">
+  <!--<ItemGroup Condition="!Exists('$(MSBuildExtensionsPath)\Xamarin\Android')">-->
+  <ItemGroup>
     <ProjectReference Remove="src/Android/**/*.*proj" />
     <ProjectReference Remove="samples/ControlCatalog.Android/ControlCatalog.Android.csproj" />
   </ItemGroup>
diff --git a/native/Avalonia.Native/inc/avalonia-native.h b/native/Avalonia.Native/inc/avalonia-native.h
index 36e16c24d1..e54f3fa6a7 100644
--- a/native/Avalonia.Native/inc/avalonia-native.h
+++ b/native/Avalonia.Native/inc/avalonia-native.h
@@ -52,6 +52,7 @@ struct AvnScreen
 {
     AvnRect Bounds;
     AvnRect WorkingArea;
+    float PixelDensity;
     bool Primary;
 };
 
@@ -187,7 +188,6 @@ AVNCOM(IAvnWindowBase, 02) : IUnknown
     virtual HRESULT Close() = 0;
     virtual HRESULT Activate () = 0;
     virtual HRESULT GetClientSize(AvnSize*ret) = 0;
-    virtual HRESULT GetMaxClientSize(AvnSize* ret) = 0;
     virtual HRESULT GetScaling(double*ret)=0;
     virtual HRESULT SetMinMaxSize(AvnSize minSize, AvnSize maxSize) = 0;
     virtual HRESULT Resize(double width, double height) = 0;
diff --git a/native/Avalonia.Native/src/OSX/Screens.mm b/native/Avalonia.Native/src/OSX/Screens.mm
index 9d436b98c5..e7f009787a 100644
--- a/native/Avalonia.Native/src/OSX/Screens.mm
+++ b/native/Avalonia.Native/src/OSX/Screens.mm
@@ -38,6 +38,8 @@ class Screens : public ComSingleObject<IAvnScreens, &IID_IAvnScreens>
             ret->WorkingArea.Height = [screen visibleFrame].size.height;
             ret->WorkingArea.Width = [screen visibleFrame].size.width;
             
+            ret->PixelDensity = [screen backingScaleFactor];
+            
             ret->Primary = index == 0;
             
             return S_OK;
diff --git a/native/Avalonia.Native/src/OSX/window.mm b/native/Avalonia.Native/src/OSX/window.mm
index bfa33eb259..3347d58004 100644
--- a/native/Avalonia.Native/src/OSX/window.mm
+++ b/native/Avalonia.Native/src/OSX/window.mm
@@ -54,7 +54,6 @@ public:
     FORWARD_IUNKNOWN()
     virtual ~WindowBaseImpl()
     {
-        NSDebugLog(@"~WindowBaseImpl()");
         View = NULL;
         Window = NULL;
     }
@@ -161,22 +160,6 @@ public:
         }
     }
     
-    virtual HRESULT GetMaxClientSize(AvnSize* ret) override
-    {
-        @autoreleasepool
-        {
-            if(ret == nullptr)
-                return E_POINTER;
-            
-            auto size = [NSScreen.screens objectAtIndex:0].frame.size;
-            
-            ret->Height = size.height;
-            ret->Width = size.width;
-            
-            return S_OK;
-        }
-    }
-    
     virtual HRESULT GetScaling (double* ret) override
     {
         @autoreleasepool
@@ -369,12 +352,9 @@ public:
 
     virtual void UpdateCursor()
     {
-        [View resetCursorRects];
         if (cursor != nil)
         {
-             auto rect = [Window frame];
-             [View addCursorRect:rect cursor:cursor];
-             [cursor set];
+            [cursor set];
         }
     }
     
@@ -416,8 +396,8 @@ private:
     INHERIT_INTERFACE_MAP(WindowBaseImpl)
     INTERFACE_MAP_ENTRY(IAvnWindow, IID_IAvnWindow)
     END_INTERFACE_MAP()
-    virtual ~WindowImpl(){
-        NSDebugLog(@"~WindowImpl");
+    virtual ~WindowImpl()
+    {
     }
     
     ComPtr<IAvnWindowEvents> WindowEvents;
@@ -425,6 +405,7 @@ private:
     {
         WindowEvents = events;
         [Window setCanBecomeKeyAndMain];
+        [Window disableCursorRects];
     }
     
     virtual HRESULT Show () override
@@ -664,10 +645,8 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
 
 - (void)dealloc
 {
-    NSDebugLog(@"AvnView dealloc");
 }
 
-
 - (void)onClosed
 {
     _parent = NULL;
@@ -1067,7 +1046,6 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
 
 - (void)dealloc
 {
-    NSDebugLog(@"AvnWindow dealloc");
 }
 
 - (void)pollModalSession:(nonnull NSModalSession)session
diff --git a/samples/BindingDemo/MainWindow.xaml b/samples/BindingDemo/MainWindow.xaml
index a232a06383..b57a9a0a9e 100644
--- a/samples/BindingDemo/MainWindow.xaml
+++ b/samples/BindingDemo/MainWindow.xaml
@@ -24,6 +24,9 @@
             <TextBox Watermark="Two Way" UseFloatingWatermark="True" Text="{Binding Path=StringValue}" Name="first"/>
             <TextBox Watermark="One Way" UseFloatingWatermark="True" Text="{Binding Path=StringValue, Mode=OneWay}"/>
             <TextBox Watermark="One Time" UseFloatingWatermark="True" Text="{Binding Path=StringValue, Mode=OneTime}"/>
+            <!-- Removed due to #2983: reinstate when that's fixed.
+              <TextBox Watermark="One Way to Source" UseFloatingWatermark="True" Text="{Binding Path=StringValue, Mode=OneWayToSource}"/>
+            -->
           </StackPanel>
           <StackPanel Margin="18" Spacing="4" Width="200">
             <TextBlock FontSize="16" Text="Collection Bindings"/>
diff --git a/samples/BindingDemo/ViewModels/MainWindowViewModel.cs b/samples/BindingDemo/ViewModels/MainWindowViewModel.cs
index 858fb5159a..22d01e0765 100644
--- a/samples/BindingDemo/ViewModels/MainWindowViewModel.cs
+++ b/samples/BindingDemo/ViewModels/MainWindowViewModel.cs
@@ -1,10 +1,11 @@
 using System;
 using System.Collections.ObjectModel;
 using System.Linq;
-using ReactiveUI;
+using System.Reactive;
 using System.Reactive.Linq;
 using System.Threading.Tasks;
 using System.Threading;
+using ReactiveUI;
 
 namespace BindingDemo.ViewModels
 {
@@ -56,7 +57,7 @@ namespace BindingDemo.ViewModels
 
         public ObservableCollection<TestItem> Items { get; }
         public ObservableCollection<TestItem> SelectedItems { get; }
-        public ReactiveCommand ShuffleItems { get; }
+        public ReactiveCommand<Unit, Unit> ShuffleItems { get; }
 
         public string BooleanString
         {
@@ -89,7 +90,7 @@ namespace BindingDemo.ViewModels
         }
 
         public IObservable<string> CurrentTimeObservable { get; }
-        public ReactiveCommand StringValueCommand { get; }
+        public ReactiveCommand<object, Unit> StringValueCommand { get; }
 
         public DataAnnotationsErrorViewModel DataAnnotationsValidation { get; } = new DataAnnotationsErrorViewModel();
         public ExceptionErrorViewModel ExceptionDataValidation { get; } = new ExceptionErrorViewModel();
diff --git a/samples/ControlCatalog/Pages/ScreenPage.cs b/samples/ControlCatalog/Pages/ScreenPage.cs
index 13c1667ed2..d775eb9635 100644
--- a/samples/ControlCatalog/Pages/ScreenPage.cs
+++ b/samples/ControlCatalog/Pages/ScreenPage.cs
@@ -57,12 +57,15 @@ namespace ControlCatalog.Pages
                     
                     text.Text = $"WorkArea: {screen.WorkingArea.Width}:{screen.WorkingArea.Height}";
                     context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 20), text);
+
+                    text.Text = $"Scaling: {screen.PixelDensity * 100}%";
+                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 40), text);
                     
                     text.Text = $"Primary: {screen.Primary}";
-                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 40), text);
+                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 60), text);
                     
                     text.Text = $"Current: {screen.Equals(w.Screens.ScreenFromBounds(new PixelRect(w.Position, PixelSize.FromSize(w.Bounds.Size, scaling))))}";
-                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 60), text);
+                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 80), text);
                 }
 
             context.DrawRectangle(p, new Rect(w.Position.X / 10f + Math.Abs(_leftMost), w.Position.Y / 10, w.Bounds.Width / 10, w.Bounds.Height / 10));
diff --git a/samples/RenderDemo/ViewModels/MainWindowViewModel.cs b/samples/RenderDemo/ViewModels/MainWindowViewModel.cs
index 0cb5e1b87b..d2d789a687 100644
--- a/samples/RenderDemo/ViewModels/MainWindowViewModel.cs
+++ b/samples/RenderDemo/ViewModels/MainWindowViewModel.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Reactive;
 using ReactiveUI;
 
 namespace RenderDemo.ViewModels
@@ -26,7 +27,7 @@ namespace RenderDemo.ViewModels
             set { this.RaiseAndSetIfChanged(ref drawFps, value); }
         }
 
-        public ReactiveCommand ToggleDrawDirtyRects { get; }
-        public ReactiveCommand ToggleDrawFps { get; }
+        public ReactiveCommand<Unit, bool> ToggleDrawDirtyRects { get; }
+        public ReactiveCommand<Unit, bool> ToggleDrawFps { get; }
     }
 }
diff --git a/samples/VirtualizationDemo/ViewModels/MainWindowViewModel.cs b/samples/VirtualizationDemo/ViewModels/MainWindowViewModel.cs
index 93fe09a156..649c64ab1d 100644
--- a/samples/VirtualizationDemo/ViewModels/MainWindowViewModel.cs
+++ b/samples/VirtualizationDemo/ViewModels/MainWindowViewModel.cs
@@ -4,10 +4,10 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reactive;
 using Avalonia.Collections;
 using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
-using ReactiveUI.Legacy;
 using ReactiveUI;
 using Avalonia.Layout;
 
@@ -18,7 +18,7 @@ namespace VirtualizationDemo.ViewModels
         private int _itemCount = 200;
         private string _newItemString = "New Item";
         private int _newItemIndex;
-        private IReactiveList<ItemViewModel> _items;
+        private AvaloniaList<ItemViewModel> _items;
         private string _prefix = "Item";
         private ScrollBarVisibility _horizontalScrollBarVisibility = ScrollBarVisibility.Auto;
         private ScrollBarVisibility _verticalScrollBarVisibility = ScrollBarVisibility.Auto;
@@ -54,7 +54,7 @@ namespace VirtualizationDemo.ViewModels
         public AvaloniaList<ItemViewModel> SelectedItems { get; } 
             = new AvaloniaList<ItemViewModel>();
 
-        public IReactiveList<ItemViewModel> Items
+        public AvaloniaList<ItemViewModel> Items
         {
             get { return _items; }
             private set { this.RaiseAndSetIfChanged(ref _items, value); }
@@ -93,11 +93,11 @@ namespace VirtualizationDemo.ViewModels
         public IEnumerable<ItemVirtualizationMode> VirtualizationModes => 
             Enum.GetValues(typeof(ItemVirtualizationMode)).Cast<ItemVirtualizationMode>();
 
-        public ReactiveCommand AddItemCommand { get; private set; }
-        public ReactiveCommand RecreateCommand { get; private set; }
-        public ReactiveCommand RemoveItemCommand { get; private set; }
-        public ReactiveCommand SelectFirstCommand { get; private set; }
-        public ReactiveCommand SelectLastCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> AddItemCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> RecreateCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> RemoveItemCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> SelectFirstCommand { get; private set; }
+        public ReactiveCommand<Unit, Unit> SelectLastCommand { get; private set; }
 
         public void RandomizeSize()
         {
@@ -123,7 +123,7 @@ namespace VirtualizationDemo.ViewModels
             {
                 var items = Enumerable.Range(0, count)
                     .Select(x => new ItemViewModel(x));
-                Items = new ReactiveList<ItemViewModel>(items);
+                Items = new AvaloniaList<ItemViewModel>(items);
             }
             else if (count > Items.Count)
             {
@@ -162,7 +162,7 @@ namespace VirtualizationDemo.ViewModels
             _prefix = _prefix == "Item" ? "Recreated" : "Item";
             var items = Enumerable.Range(0, _itemCount)
                 .Select(x => new ItemViewModel(x, _prefix));
-            Items = new ReactiveList<ItemViewModel>(items);
+            Items = new AvaloniaList<ItemViewModel>(items);
         }
 
         private void SelectItem(int index)
diff --git a/src/Avalonia.Animation/Animatable.cs b/src/Avalonia.Animation/Animatable.cs
index 2c321b8b28..ca45fb8c4d 100644
--- a/src/Avalonia.Animation/Animatable.cs
+++ b/src/Avalonia.Animation/Animatable.cs
@@ -55,6 +55,11 @@ namespace Avalonia.Animation
             }
             set
             {
+                if (value is null)
+                    return;
+
+                if (_previousTransitions is null)
+                    _previousTransitions = new Dictionary<AvaloniaProperty, IDisposable>();
 
                 SetAndRaise(TransitionsProperty, ref _transitions, value);
             }
@@ -70,7 +75,7 @@ namespace Avalonia.Animation
             if (_transitions is null || _previousTransitions is null || e.Priority == BindingPriority.Animation) return;
 
             // PERF-SENSITIVE: Called on every property change. Don't use LINQ here (too many allocations).
-            foreach (var transition in Transitions)
+            foreach (var transition in _transitions)
             {
                 if (transition.Property == e.Property)
                 {
diff --git a/src/Avalonia.Base/Data/Core/ExpressionNode.cs b/src/Avalonia.Base/Data/Core/ExpressionNode.cs
index ce40b3e517..c2e5c8e4f3 100644
--- a/src/Avalonia.Base/Data/Core/ExpressionNode.cs
+++ b/src/Avalonia.Base/Data/Core/ExpressionNode.cs
@@ -8,9 +8,13 @@ namespace Avalonia.Data.Core
     public abstract class ExpressionNode
     {
         private static readonly object CacheInvalid = new object();
+
         protected static readonly WeakReference<object> UnsetReference = 
             new WeakReference<object>(AvaloniaProperty.UnsetValue);
 
+        protected static readonly WeakReference<object> NullReference =
+            new WeakReference<object>(null);
+
         private WeakReference<object> _target = UnsetReference;
         private Action<object> _subscriber;
         private bool _listening;
@@ -98,7 +102,7 @@ namespace Avalonia.Data.Core
 
             if (notification == null)
             {
-                LastValue = new WeakReference<object>(value);
+                LastValue = value != null ? new WeakReference<object>(value) : NullReference;
 
                 if (Next != null)
                 {
@@ -111,7 +115,7 @@ namespace Avalonia.Data.Core
             }
             else
             {
-                LastValue = new WeakReference<object>(notification.Value);
+                LastValue = notification.Value != null ? new WeakReference<object>(notification.Value) : NullReference;
 
                 if (Next != null)
                 {
@@ -136,8 +140,8 @@ namespace Avalonia.Data.Core
             }
             else if (target != AvaloniaProperty.UnsetValue)
             {
-                StartListeningCore(_target);
                 _listening = true;
+                StartListeningCore(_target);
             }
             else
             {
diff --git a/src/Avalonia.Base/Data/Core/Plugins/InpcPropertyAccessorPlugin.cs b/src/Avalonia.Base/Data/Core/Plugins/InpcPropertyAccessorPlugin.cs
index 4716b45340..cbceb58204 100644
--- a/src/Avalonia.Base/Data/Core/Plugins/InpcPropertyAccessorPlugin.cs
+++ b/src/Avalonia.Base/Data/Core/Plugins/InpcPropertyAccessorPlugin.cs
@@ -103,8 +103,8 @@ namespace Avalonia.Data.Core.Plugins
 
             protected override void SubscribeCore()
             {
-                SendCurrentValue();
                 SubscribeToChanges();
+                SendCurrentValue();
             }
 
             protected override void UnsubscribeCore()
diff --git a/src/Avalonia.Base/Data/Core/SettableNode.cs b/src/Avalonia.Base/Data/Core/SettableNode.cs
index eb98b9e8d6..d0a918dc88 100644
--- a/src/Avalonia.Base/Data/Core/SettableNode.cs
+++ b/src/Avalonia.Base/Data/Core/SettableNode.cs
@@ -29,6 +29,11 @@ namespace Avalonia.Data.Core
 
             if (!isLastValueAlive)
             {
+                if (value == null && LastValue == NullReference)
+                {
+                    return true;
+                }
+
                 return false;
             }
 
diff --git a/src/Avalonia.Base/PriorityBindingEntry.cs b/src/Avalonia.Base/PriorityBindingEntry.cs
index 95add0dfac..7f5415c2d8 100644
--- a/src/Avalonia.Base/PriorityBindingEntry.cs
+++ b/src/Avalonia.Base/PriorityBindingEntry.cs
@@ -99,37 +99,42 @@ namespace Avalonia
 
         void IObserver<object>.OnNext(object value)
         {
-            void Signal()
+            void Signal(PriorityBindingEntry instance, object newValue)
             {
-                var notification = value as BindingNotification;
+                var notification = newValue as BindingNotification;
 
                 if (notification != null)
                 {
                     if (notification.HasValue || notification.ErrorType == BindingErrorType.Error)
                     {
-                        Value = notification.Value;
-                        _owner.Changed(this);
+                        instance.Value = notification.Value;
+                        instance._owner.Changed(instance);
                     }
 
                     if (notification.ErrorType != BindingErrorType.None)
                     {
-                        _owner.Error(this, notification);
+                        instance._owner.Error(instance, notification);
                     }
                 }
                 else
                 {
-                    Value = value;
-                    _owner.Changed(this);
+                    instance.Value = newValue;
+                    instance._owner.Changed(instance);
                 }
             }
 
             if (Dispatcher.UIThread.CheckAccess())
             {
-                Signal();
+                Signal(this, value);
             }
             else
             {
-                Dispatcher.UIThread.Post(Signal);
+                // To avoid allocating closure in the outer scope we need to capture variables
+                // locally. This allows us to skip most of the allocations when on UI thread.
+                var instance = this;
+                var newValue = value;
+
+                Dispatcher.UIThread.Post(() => Signal(instance, newValue));
             }
         }
 
diff --git a/src/Avalonia.Base/PriorityLevel.cs b/src/Avalonia.Base/PriorityLevel.cs
index 909558b0ce..6366911e77 100644
--- a/src/Avalonia.Base/PriorityLevel.cs
+++ b/src/Avalonia.Base/PriorityLevel.cs
@@ -110,20 +110,7 @@ namespace Avalonia
 
             entry.Start(binding);
 
-            return Disposable.Create(() =>
-            {
-                if (!entry.HasCompleted)
-                {
-                    Bindings.Remove(node);
-
-                    entry.Dispose();
-
-                    if (entry.Index >= ActiveBindingIndex)
-                    {
-                        ActivateFirstBinding();
-                    }
-                }
-            });
+            return new RemoveBindingDisposable(node, Bindings, this);
         }
 
         /// <summary>
@@ -191,5 +178,39 @@ namespace Avalonia
             ActiveBindingIndex = -1;
             Owner.LevelValueChanged(this);
         }
+
+        private sealed class RemoveBindingDisposable : IDisposable
+        {
+            private readonly LinkedListNode<PriorityBindingEntry> _binding;
+            private readonly LinkedList<PriorityBindingEntry> _bindings;
+            private readonly PriorityLevel _priorityLevel;
+
+            public RemoveBindingDisposable(
+                LinkedListNode<PriorityBindingEntry> binding,
+                LinkedList<PriorityBindingEntry> bindings,
+                PriorityLevel priorityLevel)
+            {
+                _binding = binding;
+                _bindings = bindings;
+                _priorityLevel = priorityLevel;
+            }
+
+            public void Dispose()
+            {
+                PriorityBindingEntry entry = _binding.Value;
+
+                if (!entry.HasCompleted)
+                {
+                    _bindings.Remove(_binding);
+
+                    entry.Dispose();
+
+                    if (entry.Index >= _priorityLevel.ActiveBindingIndex)
+                    {
+                        _priorityLevel.ActivateFirstBinding();
+                    }
+                }
+            }
+        }
     }
 }
diff --git a/src/Avalonia.Controls/Button.cs b/src/Avalonia.Controls/Button.cs
index b09d3bddff..d39ea73828 100644
--- a/src/Avalonia.Controls/Button.cs
+++ b/src/Avalonia.Controls/Button.cs
@@ -64,6 +64,12 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<bool> IsDefaultProperty =
             AvaloniaProperty.Register<Button, bool>(nameof(IsDefault));
 
+        /// <summary>
+        /// Defines the <see cref="IsCancelProperty"/> property.
+        /// </summary>
+        public static readonly StyledProperty<bool> IsCancelProperty =
+            AvaloniaProperty.Register<Button, bool>(nameof(IsCancel));
+
         /// <summary>
         /// Defines the <see cref="Click"/> event.
         /// </summary>
@@ -84,6 +90,7 @@ namespace Avalonia.Controls
             FocusableProperty.OverrideDefaultValue(typeof(Button), true);
             CommandProperty.Changed.Subscribe(CommandChanged);
             IsDefaultProperty.Changed.Subscribe(IsDefaultChanged);
+            IsCancelProperty.Changed.Subscribe(IsCancelChanged);
             PseudoClass<Button>(IsPressedProperty, ":pressed");
         }
 
@@ -142,6 +149,16 @@ namespace Avalonia.Controls
             set { SetValue(IsDefaultProperty, value); }
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether the button is the Cancel button for the
+        /// window.
+        /// </summary>
+        public bool IsCancel
+        {
+            get { return GetValue(IsCancelProperty); }
+            set { SetValue(IsCancelProperty, value); }
+        }
+
         public bool IsPressed
         {
             get { return GetValue(IsPressedProperty); }
@@ -162,6 +179,13 @@ namespace Avalonia.Controls
                     ListenForDefault(inputElement);
                 }
             }
+            if (IsCancel)
+            {
+                if (e.Root is IInputElement inputElement)
+                {
+                    ListenForCancel(inputElement);
+                }
+            }
         }
 
         /// <inheritdoc/>
@@ -351,6 +375,28 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Called when the <see cref="IsCancel"/> property changes.
+        /// </summary>
+        /// <param name="e">The event args.</param>
+        private static void IsCancelChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            var button = e.Sender as Button;
+            var isCancel = (bool)e.NewValue;
+
+            if (button?.VisualRoot is IInputElement inputRoot)
+            {
+                if (isCancel)
+                {
+                    button.ListenForCancel(inputRoot);
+                }
+                else
+                {
+                    button.StopListeningForCancel(inputRoot);
+                }
+            }
+        }
+
         /// <summary>
         /// Called when the <see cref="ICommand.CanExecuteChanged"/> event fires.
         /// </summary>
@@ -373,7 +419,16 @@ namespace Avalonia.Controls
         /// <param name="root">The input root.</param>
         private void ListenForDefault(IInputElement root)
         {
-            root.AddHandler(KeyDownEvent, RootKeyDown);
+            root.AddHandler(KeyDownEvent, RootDefaultKeyDown);
+        }
+
+        /// <summary>
+        /// Starts listening for the Escape key when the button <see cref="IsCancel"/>.
+        /// </summary>
+        /// <param name="root">The input root.</param>
+        private void ListenForCancel(IInputElement root)
+        {
+            root.AddHandler(KeyDownEvent, RootCancelKeyDown);
         }
 
         /// <summary>
@@ -382,7 +437,16 @@ namespace Avalonia.Controls
         /// <param name="root">The input root.</param>
         private void StopListeningForDefault(IInputElement root)
         {
-            root.RemoveHandler(KeyDownEvent, RootKeyDown);
+            root.RemoveHandler(KeyDownEvent, RootDefaultKeyDown);
+        }
+
+        /// <summary>
+        /// Stops listening for the Escape key when the button is no longer <see cref="IsCancel"/>.
+        /// </summary>
+        /// <param name="root">The input root.</param>
+        private void StopListeningForCancel(IInputElement root)
+        {
+            root.RemoveHandler(KeyDownEvent, RootCancelKeyDown);
         }
 
         /// <summary>
@@ -390,12 +454,25 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="sender">The event sender.</param>
         /// <param name="e">The event args.</param>
-        private void RootKeyDown(object sender, KeyEventArgs e)
+        private void RootDefaultKeyDown(object sender, KeyEventArgs e)
         {
             if (e.Key == Key.Enter && IsVisible && IsEnabled)
             {
                 OnClick();
             }
         }
+
+        /// <summary>
+        /// Called when a key is pressed on the input root and the button <see cref="IsCancel"/>.
+        /// </summary>
+        /// <param name="sender">The event sender.</param>
+        /// <param name="e">The event args.</param>
+        private void RootCancelKeyDown(object sender, KeyEventArgs e)
+        {
+            if (e.Key == Key.Escape && IsVisible && IsEnabled)
+            {
+                OnClick();
+            }
+        }
     }
 }
diff --git a/src/Avalonia.Controls/Platform/Screen.cs b/src/Avalonia.Controls/Platform/Screen.cs
index e7c811235c..976faed3fd 100644
--- a/src/Avalonia.Controls/Platform/Screen.cs
+++ b/src/Avalonia.Controls/Platform/Screen.cs
@@ -2,14 +2,17 @@
 {
     public class Screen
     {
+        public double PixelDensity { get; }
+
         public PixelRect Bounds { get; }
 
         public PixelRect WorkingArea { get; }
 
         public bool Primary { get; }
         
-        public Screen(PixelRect bounds, PixelRect workingArea, bool primary)
+        public Screen(double pixelDensity, PixelRect bounds, PixelRect workingArea, bool primary)
         {
+            this.PixelDensity = pixelDensity;
             this.Bounds = bounds;
             this.WorkingArea = workingArea;
             this.Primary = primary;
diff --git a/src/Avalonia.Controls/Primitives/Popup.cs b/src/Avalonia.Controls/Primitives/Popup.cs
index 5ddbed5944..b3f86e8a76 100644
--- a/src/Avalonia.Controls/Primitives/Popup.cs
+++ b/src/Avalonia.Controls/Primitives/Popup.cs
@@ -450,7 +450,14 @@ namespace Avalonia.Controls.Primitives
 
         private bool IsChildOrThis(IVisual child)
         {
-            return _popupHost != null && ((IVisual)_popupHost).FindCommonVisualAncestor(child) == _popupHost;
+            IVisual root = child.GetVisualRoot();
+            while (root is IHostedVisualTreeRoot hostedRoot )
+            {
+                if (root == this._popupHost)
+                    return true;
+                root = hostedRoot.Host?.GetVisualRoot();
+            }
+            return false;
         }
         
         public bool IsInsidePopup(IVisual visual)
diff --git a/src/Avalonia.Controls/Primitives/PopupPositioning/ManagedPopupPositionerPopupImplHelper.cs b/src/Avalonia.Controls/Primitives/PopupPositioning/ManagedPopupPositionerPopupImplHelper.cs
index bb701da651..8e7e429a73 100644
--- a/src/Avalonia.Controls/Primitives/PopupPositioning/ManagedPopupPositionerPopupImplHelper.cs
+++ b/src/Avalonia.Controls/Primitives/PopupPositioning/ManagedPopupPositionerPopupImplHelper.cs
@@ -32,7 +32,7 @@ namespace Avalonia.Controls.Primitives.PopupPositioning
             {
                 // Popup positioner operates with abstract coordinates, but in our case they are pixel ones
                 var point = _parent.PointToScreen(default);
-                var size = PixelSize.FromSize(_parent.ClientSize, _parent.Scaling);
+                var size = TranslateSize(_parent.ClientSize);
                 return new Rect(point.X, point.Y, size.Width, size.Height);
 
             }
@@ -43,8 +43,8 @@ namespace Avalonia.Controls.Primitives.PopupPositioning
             _moveResize(new PixelPoint((int)devicePoint.X, (int)devicePoint.Y), virtualSize, _parent.Scaling);
         }
 
-        public Point TranslatePoint(Point pt) => pt * _parent.Scaling;
+        public virtual Point TranslatePoint(Point pt) => pt * _parent.Scaling;
 
-        public Size TranslateSize(Size size) => size * _parent.Scaling;
+        public virtual Size TranslateSize(Size size) => size * _parent.Scaling;
     }
 }
diff --git a/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs b/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
index cc0c5f52be..a50175bdee 100644
--- a/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
+++ b/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
@@ -304,6 +304,11 @@ namespace Avalonia.Controls.Primitives
         {
             base.ItemsCollectionChanged(sender, e);
 
+            if (_updateCount > 0)
+            {
+                return;
+            }
+
             switch (e.Action)
             {
                 case NotifyCollectionChangedAction.Add:
@@ -1071,13 +1076,20 @@ namespace Avalonia.Controls.Primitives
 
         private void UpdateFinished()
         {
-            if (_updateSelectedIndex != int.MinValue)
+            if (_updateSelectedItem != null)
             {
-                SelectedIndex = _updateSelectedIndex;
+                SelectedItem = _updateSelectedItem;
             }
-            else if (_updateSelectedItem != null)
+            else
             {
-                SelectedItem = _updateSelectedItem;
+                if (ItemCount == 0 && SelectedIndex != -1)
+                {
+                    SelectedIndex = -1;
+                }
+                else
+                {
+                    SelectedIndex = _updateSelectedIndex != int.MinValue ? _updateSelectedIndex : 0;
+                }
             }
         }
 
diff --git a/src/Avalonia.Controls/Repeater/ViewManager.cs b/src/Avalonia.Controls/Repeater/ViewManager.cs
index 833e708e9e..3e09a5b3ee 100644
--- a/src/Avalonia.Controls/Repeater/ViewManager.cs
+++ b/src/Avalonia.Controls/Repeater/ViewManager.cs
@@ -128,8 +128,7 @@ namespace Avalonia.Controls
 
         private void MoveFocusFromClearedIndex(int clearedIndex)
         {
-            IControl focusedChild = null;
-            var focusCandidate = FindFocusCandidate(clearedIndex, focusedChild);
+            var focusCandidate = FindFocusCandidate(clearedIndex, out var focusedChild);
             if (focusCandidate != null)
             {
                 focusCandidate.Focus();
@@ -145,7 +144,7 @@ namespace Avalonia.Controls
             }
         }
 
-        IControl FindFocusCandidate(int clearedIndex, IControl focusedChild)
+        IControl FindFocusCandidate(int clearedIndex, out IControl focusedChild)
         {
             // Walk through all the children and find elements with index before and after the cleared index.
             // Note that during a delete the next element would now have the same index.
@@ -183,7 +182,7 @@ namespace Avalonia.Controls
 
             // TODO: Find the next element if one exists, if not use the previous element.
             // If the container itself is not focusable, find a descendent that is.
-
+            focusedChild = nextElement;
             return nextElement;
         }
 
diff --git a/src/Avalonia.Controls/WrapPanel.cs b/src/Avalonia.Controls/WrapPanel.cs
index 3acf341c35..7c88401615 100644
--- a/src/Avalonia.Controls/WrapPanel.cs
+++ b/src/Avalonia.Controls/WrapPanel.cs
@@ -15,7 +15,7 @@ namespace Avalonia.Controls
     /// Positions child elements in sequential position from left to right, 
     /// breaking content to the next line at the edge of the containing box. 
     /// Subsequent ordering happens sequentially from top to bottom or from right to left, 
-    /// depending on the value of the Orientation property.
+    /// depending on the value of the <see cref="Orientation"/> property.
     /// </summary>
     public class WrapPanel : Panel, INavigableContainer
     {
@@ -25,6 +25,18 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<Orientation> OrientationProperty =
             AvaloniaProperty.Register<WrapPanel, Orientation>(nameof(Orientation), defaultValue: Orientation.Horizontal);
 
+        /// <summary>
+        /// Defines the <see cref="ItemWidth"/> property.
+        /// </summary>
+        public static readonly StyledProperty<double> ItemWidthProperty =
+            AvaloniaProperty.Register<WrapPanel, double>(nameof(ItemWidth), double.NaN);
+
+        /// <summary>
+        /// Defines the <see cref="ItemHeight"/> property.
+        /// </summary>
+        public static readonly StyledProperty<double> ItemHeightProperty =
+            AvaloniaProperty.Register<WrapPanel, double>(nameof(ItemHeight), double.NaN);
+
         /// <summary>
         /// Initializes static members of the <see cref="WrapPanel"/> class.
         /// </summary>
@@ -42,6 +54,24 @@ namespace Avalonia.Controls
             set { SetValue(OrientationProperty, value); }
         }
 
+        /// <summary>
+        /// Gets or sets the width of all items in the WrapPanel.
+        /// </summary>
+        public double ItemWidth
+        {
+            get { return GetValue(ItemWidthProperty); }
+            set { SetValue(ItemWidthProperty, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the height of all items in the WrapPanel.
+        /// </summary>
+        public double ItemHeight
+        {
+            get { return GetValue(ItemHeightProperty); }
+            set { SetValue(ItemHeightProperty, value); }
+        }
+
         /// <summary>
         /// Gets the next control in the specified direction.
         /// </summary>
@@ -51,7 +81,9 @@ namespace Avalonia.Controls
         /// <returns>The control.</returns>
         IInputElement INavigableContainer.GetControl(NavigationDirection direction, IInputElement from, bool wrap)
         {
-            var horiz = Orientation == Orientation.Horizontal;
+            var orientation = Orientation;
+            var children = Children;
+            bool horiz = orientation == Orientation.Horizontal;
             int index = Children.IndexOf((IControl)from);
 
             switch (direction)
@@ -60,7 +92,7 @@ namespace Avalonia.Controls
                     index = 0;
                     break;
                 case NavigationDirection.Last:
-                    index = Children.Count - 1;
+                    index = children.Count - 1;
                     break;
                 case NavigationDirection.Next:
                     ++index;
@@ -82,9 +114,9 @@ namespace Avalonia.Controls
                     break;
             }
 
-            if (index >= 0 && index < Children.Count)
+            if (index >= 0 && index < children.Count)
             {
-                return Children[index];
+                return children[index];
             }
             else
             {
@@ -95,116 +127,140 @@ namespace Avalonia.Controls
         /// <inheritdoc/>
         protected override Size MeasureOverride(Size constraint)
         {
-            var curLineSize = new UVSize(Orientation);
-            var panelSize = new UVSize(Orientation);
-            var uvConstraint = new UVSize(Orientation, constraint.Width, constraint.Height);
-
-            var childConstraint = new Size(constraint.Width, constraint.Height);
-
-            for (int i = 0, count = Children.Count; i < count; i++)
+            double itemWidth = ItemWidth;
+            double itemHeight = ItemHeight;
+            var orientation = Orientation;
+            var children = Children;
+            var curLineSize = new UVSize(orientation);
+            var panelSize = new UVSize(orientation);
+            var uvConstraint = new UVSize(orientation, constraint.Width, constraint.Height);
+            bool itemWidthSet = !double.IsNaN(itemWidth);
+            bool itemHeightSet = !double.IsNaN(itemHeight);
+
+            var childConstraint = new Size(
+                itemWidthSet ? itemWidth : constraint.Width,
+                itemHeightSet ? itemHeight : constraint.Height);
+            
+            for (int i = 0, count = children.Count; i < count; i++)
             {
-                var child = Children[i];
-                if (child == null) continue;
-
-                //Flow passes its own constrint to children
-                child.Measure(childConstraint);
-
-                //this is the size of the child in UV space
-                var sz = new UVSize(Orientation, child.DesiredSize.Width, child.DesiredSize.Height);
-
-                if (MathUtilities.GreaterThan(curLineSize.U + sz.U, uvConstraint.U)) //need to switch to another line
+                var child = children[i];
+                if (child != null)
                 {
-                    panelSize.U = Max(curLineSize.U, panelSize.U);
-                    panelSize.V += curLineSize.V;
-                    curLineSize = sz;
+                    // Flow passes its own constraint to children
+                    child.Measure(childConstraint);
+
+                    // This is the size of the child in UV space
+                    var sz = new UVSize(orientation,
+                        itemWidthSet ? itemWidth : child.DesiredSize.Width,
+                        itemHeightSet ? itemHeight : child.DesiredSize.Height);
 
-                    if (MathUtilities.GreaterThan(sz.U, uvConstraint.U)) //the element is wider then the constrint - give it a separate line                    
+                    if (MathUtilities.GreaterThan(curLineSize.U + sz.U, uvConstraint.U)) // Need to switch to another line
                     {
-                        panelSize.U = Max(sz.U, panelSize.U);
-                        panelSize.V += sz.V;
-                        curLineSize = new UVSize(Orientation);
+                        panelSize.U = Max(curLineSize.U, panelSize.U);
+                        panelSize.V += curLineSize.V;
+                        curLineSize = sz;
+
+                        if (MathUtilities.GreaterThan(sz.U, uvConstraint.U)) // The element is wider then the constraint - give it a separate line                    
+                        {
+                            panelSize.U = Max(sz.U, panelSize.U);
+                            panelSize.V += sz.V;
+                            curLineSize = new UVSize(orientation);
+                        }
+                    }
+                    else // Continue to accumulate a line
+                    {
+                        curLineSize.U += sz.U;
+                        curLineSize.V = Max(sz.V, curLineSize.V);
                     }
-                }
-                else //continue to accumulate a line
-                {
-                    curLineSize.U += sz.U;
-                    curLineSize.V = Max(sz.V, curLineSize.V);
                 }
             }
 
-            //the last line size, if any should be added
+            // The last line size, if any should be added
             panelSize.U = Max(curLineSize.U, panelSize.U);
             panelSize.V += curLineSize.V;
 
-            //go from UV space to W/H space
+            // Go from UV space to W/H space
             return new Size(panelSize.Width, panelSize.Height);
         }
 
         /// <inheritdoc/>
         protected override Size ArrangeOverride(Size finalSize)
         {
+            double itemWidth = ItemWidth;
+            double itemHeight = ItemHeight;
+            var orientation = Orientation;
+            var children = Children;
             int firstInLine = 0;
             double accumulatedV = 0;
-            UVSize curLineSize = new UVSize(Orientation);
-            UVSize uvFinalSize = new UVSize(Orientation, finalSize.Width, finalSize.Height);
-
-            for (int i = 0; i < Children.Count; i++)
+            double itemU = orientation == Orientation.Horizontal ? itemWidth : itemHeight;
+            var curLineSize = new UVSize(orientation);
+            var uvFinalSize = new UVSize(orientation, finalSize.Width, finalSize.Height);
+            bool itemWidthSet = !double.IsNaN(itemWidth);
+            bool itemHeightSet = !double.IsNaN(itemHeight);
+            bool useItemU = orientation == Orientation.Horizontal ? itemWidthSet : itemHeightSet;
+
+            for (int i = 0; i < children.Count; i++)
             {
-                var child = Children[i];
-                if (child == null) continue;
+                var child = children[i];
+                if (child != null)
+                {
+                    var sz = new UVSize(orientation,
+                        itemWidthSet ? itemWidth : child.DesiredSize.Width,
+                        itemHeightSet ? itemHeight : child.DesiredSize.Height);
 
-                var sz = new UVSize(Orientation, child.DesiredSize.Width, child.DesiredSize.Height);
+                    if (MathUtilities.GreaterThan(curLineSize.U + sz.U, uvFinalSize.U)) // Need to switch to another line
+                    {
+                        ArrangeLine(accumulatedV, curLineSize.V, firstInLine, i, useItemU, itemU);
 
-                if (MathUtilities.GreaterThan(curLineSize.U + sz.U, uvFinalSize.U)) //need to switch to another line
-                {
-                    arrangeLine(accumulatedV, curLineSize.V, firstInLine, i);
+                        accumulatedV += curLineSize.V;
+                        curLineSize = sz;
 
-                    accumulatedV += curLineSize.V;
-                    curLineSize = sz;
+                        if (MathUtilities.GreaterThan(sz.U, uvFinalSize.U)) // The element is wider then the constraint - give it a separate line                    
+                        {
+                            // Switch to next line which only contain one element
+                            ArrangeLine(accumulatedV, sz.V, i, ++i, useItemU, itemU);
 
-                    if (MathUtilities.GreaterThan(sz.U, uvFinalSize.U)) //the element is wider then the constraint - give it a separate line                    
+                            accumulatedV += sz.V;
+                            curLineSize = new UVSize(orientation);
+                        }
+                        firstInLine = i;
+                    }
+                    else // Continue to accumulate a line
                     {
-                        //switch to next line which only contain one element
-                        arrangeLine(accumulatedV, sz.V, i, ++i);
-
-                        accumulatedV += sz.V;
-                        curLineSize = new UVSize(Orientation);
+                        curLineSize.U += sz.U;
+                        curLineSize.V = Max(sz.V, curLineSize.V);
                     }
-                    firstInLine = i;
-                }
-                else //continue to accumulate a line
-                {
-                    curLineSize.U += sz.U;
-                    curLineSize.V = Max(sz.V, curLineSize.V);
                 }
             }
 
-            //arrange the last line, if any
-            if (firstInLine < Children.Count)
+            // Arrange the last line, if any
+            if (firstInLine < children.Count)
             {
-                arrangeLine(accumulatedV, curLineSize.V, firstInLine, Children.Count);
+                ArrangeLine(accumulatedV, curLineSize.V, firstInLine, children.Count, useItemU, itemU);
             }
 
             return finalSize;
         }
 
-        private void arrangeLine(double v, double lineV, int start, int end)
+        private void ArrangeLine(double v, double lineV, int start, int end, bool useItemU, double itemU)
         {
+            var orientation = Orientation;
+            var children = Children;
             double u = 0;
-            bool isHorizontal = (Orientation == Orientation.Horizontal);
+            bool isHorizontal = orientation == Orientation.Horizontal;
 
             for (int i = start; i < end; i++)
             {
-                var child = Children[i];
+                var child = children[i];
                 if (child != null)
                 {
-                    UVSize childSize = new UVSize(Orientation, child.DesiredSize.Width, child.DesiredSize.Height);
-                    double layoutSlotU = childSize.U;
+                    var childSize = new UVSize(orientation, child.DesiredSize.Width, child.DesiredSize.Height);
+                    double layoutSlotU = useItemU ? itemU : childSize.U;
                     child.Arrange(new Rect(
-                        (isHorizontal ? u : v),
-                        (isHorizontal ? v : u),
-                        (isHorizontal ? layoutSlotU : lineV),
-                        (isHorizontal ? lineV : layoutSlotU)));
+                        isHorizontal ? u : v,
+                        isHorizontal ? v : u,
+                        isHorizontal ? layoutSlotU : lineV,
+                        isHorizontal ? lineV : layoutSlotU));
                     u += layoutSlotU;
                 }
             }
@@ -232,12 +288,12 @@ namespace Avalonia.Controls
 
             internal double Width
             {
-                get { return (_orientation == Orientation.Horizontal ? U : V); }
+                get { return _orientation == Orientation.Horizontal ? U : V; }
                 set { if (_orientation == Orientation.Horizontal) U = value; else V = value; }
             }
             internal double Height
             {
-                get { return (_orientation == Orientation.Horizontal ? V : U); }
+                get { return _orientation == Orientation.Horizontal ? V : U; }
                 set { if (_orientation == Orientation.Horizontal) V = value; else U = value; }
             }
         }
diff --git a/src/Avalonia.DesignerSupport/Remote/Stubs.cs b/src/Avalonia.DesignerSupport/Remote/Stubs.cs
index 4ce0da60a2..16d434b614 100644
--- a/src/Avalonia.DesignerSupport/Remote/Stubs.cs
+++ b/src/Avalonia.DesignerSupport/Remote/Stubs.cs
@@ -178,6 +178,6 @@ namespace Avalonia.DesignerSupport.Remote
         public int ScreenCount => 1;
 
         public IReadOnlyList<Screen> AllScreens { get; } =
-            new Screen[] { new Screen(new PixelRect(0, 0, 4000, 4000), new PixelRect(0, 0, 4000, 4000), true) };
+            new Screen[] { new Screen(1, new PixelRect(0, 0, 4000, 4000), new PixelRect(0, 0, 4000, 4000), true) };
     }
 }
diff --git a/src/Avalonia.Native/AvaloniaNativePlatform.cs b/src/Avalonia.Native/AvaloniaNativePlatform.cs
index 0da97b915c..6d48ab3829 100644
--- a/src/Avalonia.Native/AvaloniaNativePlatform.cs
+++ b/src/Avalonia.Native/AvaloniaNativePlatform.cs
@@ -1,7 +1,6 @@
 // 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;
-using System.Diagnostics.Contracts;
 using System.Runtime.InteropServices;
 using Avalonia.Controls.Platform;
 using Avalonia.Input;
diff --git a/src/Avalonia.Native/OsxManagedPopupPositionerPopupImplHelper.cs b/src/Avalonia.Native/OsxManagedPopupPositionerPopupImplHelper.cs
new file mode 100644
index 0000000000..6c98e3c0cc
--- /dev/null
+++ b/src/Avalonia.Native/OsxManagedPopupPositionerPopupImplHelper.cs
@@ -0,0 +1,18 @@
+// 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.Primitives.PopupPositioning;
+using Avalonia.Platform;
+
+namespace Avalonia.Native
+{
+    class OsxManagedPopupPositionerPopupImplHelper : ManagedPopupPositionerPopupImplHelper
+    {
+        public OsxManagedPopupPositionerPopupImplHelper(IWindowBaseImpl parent, MoveResizeDelegate moveResize) : base(parent, moveResize)
+        {
+
+        }
+        public override Point TranslatePoint(Point pt) => pt;
+
+        public override Size TranslateSize(Size size) => size;
+    }
+}
diff --git a/src/Avalonia.Native/PopupImpl.cs b/src/Avalonia.Native/PopupImpl.cs
index f776ee0132..d7fa1052ff 100644
--- a/src/Avalonia.Native/PopupImpl.cs
+++ b/src/Avalonia.Native/PopupImpl.cs
@@ -22,7 +22,7 @@ namespace Avalonia.Native
             {
                 Init(factory.CreatePopup(e), factory.CreateScreens());
             }
-            PopupPositioner = new ManagedPopupPositioner(new ManagedPopupPositionerPopupImplHelper(parent, MoveResize));
+            PopupPositioner = new ManagedPopupPositioner(new OsxManagedPopupPositionerPopupImplHelper(parent, MoveResize));
         }
 
         private void MoveResize(PixelPoint position, Size size, double scaling)
diff --git a/src/Avalonia.Native/ScreenImpl.cs b/src/Avalonia.Native/ScreenImpl.cs
index 2afa71753e..3ec3be20d3 100644
--- a/src/Avalonia.Native/ScreenImpl.cs
+++ b/src/Avalonia.Native/ScreenImpl.cs
@@ -31,6 +31,7 @@ namespace Avalonia.Native
                     var screen = _native.GetScreen(i);
 
                     result[i] = new Screen(
+                        screen.PixelDensity,
                         screen.Bounds.ToAvaloniaPixelRect(),
                         screen.WorkingArea.ToAvaloniaPixelRect(),
                         screen.Primary);
diff --git a/src/Avalonia.Native/WindowImplBase.cs b/src/Avalonia.Native/WindowImplBase.cs
index 217fb4b078..d8ff370c45 100644
--- a/src/Avalonia.Native/WindowImplBase.cs
+++ b/src/Avalonia.Native/WindowImplBase.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Avalonia.Controls;
 using Avalonia.Controls.Platform.Surfaces;
 using Avalonia.Input;
@@ -48,6 +49,11 @@ namespace Avalonia.Native
             Screen = new ScreenImpl(screens);
             _savedLogicalSize = ClientSize;
             _savedScaling = Scaling;
+
+            var monitor = Screen.AllScreens.OrderBy(x => x.PixelDensity)
+                    .FirstOrDefault(m => m.Bounds.Contains(Position));
+
+            Resize(new Size(monitor.WorkingArea.Width * 0.75d, monitor.WorkingArea.Height * 0.7d));
         }
 
         public Size ClientSize 
@@ -300,7 +306,8 @@ namespace Avalonia.Native
             _native.BeginMoveDrag();
         }
 
-        public Size MaxClientSize => _native.GetMaxClientSize().ToAvaloniaSize();
+        public Size MaxClientSize => Screen.AllScreens.Select(s => s.Bounds.Size.ToSize(s.PixelDensity))
+            .OrderByDescending(x => x.Width + x.Height).FirstOrDefault();
 
         public void SetTopmost(bool value)
         {
diff --git a/src/Avalonia.ReactiveUI/AvaloniaActivationForViewFetcher.cs b/src/Avalonia.ReactiveUI/AvaloniaActivationForViewFetcher.cs
index cfa7a270be..5a4d625c41 100644
--- a/src/Avalonia.ReactiveUI/AvaloniaActivationForViewFetcher.cs
+++ b/src/Avalonia.ReactiveUI/AvaloniaActivationForViewFetcher.cs
@@ -27,7 +27,7 @@ namespace Avalonia.ReactiveUI
         /// <summary>
         /// Returns activation observable for activatable Avalonia view.
         /// </summary>
-        public IObservable<bool> GetActivationForView(IActivatable view)
+        public IObservable<bool> GetActivationForView(IActivatableView view)
         {
             if (!(view is IVisual visual)) return Observable.Return(false);
             if (view is WindowBase window) return GetActivationForWindowBase(window);
diff --git a/src/Avalonia.ReactiveUI/RoutedViewHost.cs b/src/Avalonia.ReactiveUI/RoutedViewHost.cs
index 05edeea683..ac5db32c14 100644
--- a/src/Avalonia.ReactiveUI/RoutedViewHost.cs
+++ b/src/Avalonia.ReactiveUI/RoutedViewHost.cs
@@ -53,7 +53,7 @@ namespace Avalonia.ReactiveUI
     /// ReactiveUI routing documentation website</see> for more info.
     /// </para>
     /// </remarks>
-    public class RoutedViewHost : TransitioningContentControl, IActivatable, IEnableLogger
+    public class RoutedViewHost : TransitioningContentControl, IActivatableView, IEnableLogger
     {
         /// <summary>
         /// <see cref="AvaloniaProperty"/> for the <see cref="Router"/> property.
diff --git a/src/Avalonia.Styling/Controls/ResourceProviderExtensions.cs b/src/Avalonia.Styling/Controls/ResourceNodeExtensions.cs
similarity index 98%
rename from src/Avalonia.Styling/Controls/ResourceProviderExtensions.cs
rename to src/Avalonia.Styling/Controls/ResourceNodeExtensions.cs
index 01112eaf2c..19a16f86c4 100644
--- a/src/Avalonia.Styling/Controls/ResourceProviderExtensions.cs
+++ b/src/Avalonia.Styling/Controls/ResourceNodeExtensions.cs
@@ -3,7 +3,7 @@ using Avalonia.Reactive;
 
 namespace Avalonia.Controls
 {
-    public static class ResourceProviderExtensions
+    public static class ResourceNodeExtensions
     {
         /// <summary>
         /// Finds the specified resource by searching up the logical tree and then global styles.
diff --git a/src/Avalonia.Themes.Default/ProgressBar.xaml b/src/Avalonia.Themes.Default/ProgressBar.xaml
index a77a2f3ad5..72271e785a 100644
--- a/src/Avalonia.Themes.Default/ProgressBar.xaml
+++ b/src/Avalonia.Themes.Default/ProgressBar.xaml
@@ -7,9 +7,7 @@
         <Border Background="{TemplateBinding Background}"
                 BorderBrush="{TemplateBinding BorderBrush}"
                 BorderThickness="{TemplateBinding BorderThickness}">
-          <Border Name="PART_Indicator"
-                  BorderThickness="1"
-                  Background="{TemplateBinding Foreground}"/>
+          <Border Name="PART_Indicator" Background="{TemplateBinding Foreground}"/>
         </Border>
       </ControlTemplate>
     </Setter>
diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
index 2fcea8c205..161cbc099e 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
@@ -53,6 +53,16 @@ namespace Avalonia.Rendering.SceneGraph
 
             if (visual.VisualRoot != null)
             {
+                if (node?.Parent != null &&
+                    visual.VisualParent != null &&
+                    node.Parent.Visual != visual.VisualParent)
+                {
+                    // The control has changed parents. Remove the node and recurse into the new parent node.
+                    ((VisualNode)node.Parent).RemoveChild(node);
+                    Deindex(scene, node);
+                    node = (VisualNode)scene.FindNode(visual.VisualParent);
+                }
+
                 if (visual.IsVisible)
                 {
                     // If the node isn't yet part of the scene, find the nearest ancestor that is.
diff --git a/src/Avalonia.X11/X11Screens.cs b/src/Avalonia.X11/X11Screens.cs
index 6f860145d3..e247a4241a 100644
--- a/src/Avalonia.X11/X11Screens.cs
+++ b/src/Avalonia.X11/X11Screens.cs
@@ -157,7 +157,7 @@ namespace Avalonia.X11
         public int ScreenCount => _impl.Screens.Length;
 
         public IReadOnlyList<Screen> AllScreens =>
-            _impl.Screens.Select(s => new Screen(s.Bounds, s.WorkingArea, s.Primary)).ToArray();
+            _impl.Screens.Select(s => new Screen(s.PixelDensity, s.Bounds, s.WorkingArea, s.Primary)).ToArray();
     }
 
     interface IX11Screens
diff --git a/src/Avalonia.X11/X11Window.cs b/src/Avalonia.X11/X11Window.cs
index 975b3d11d7..00761dfce8 100644
--- a/src/Avalonia.X11/X11Window.cs
+++ b/src/Avalonia.X11/X11Window.cs
@@ -98,14 +98,26 @@ namespace Avalonia.X11
                 valueMask |= SetWindowValuemask.ColorMap;   
             }
 
-            _handle = XCreateWindow(_x11.Display, _x11.RootWindow, 10, 10, 300, 200, 0,
+            int defaultWidth = 300, defaultHeight = 200;
+
+            if (!_popup)
+            {
+                var monitor = Screen.AllScreens.OrderBy(x => x.PixelDensity)
+                   .FirstOrDefault(m => m.Bounds.Contains(Position));
+
+                // Emulate Window 7+'s default window size behavior.
+                defaultWidth = (int)(monitor.WorkingArea.Width * 0.75d);
+                defaultHeight = (int)(monitor.WorkingArea.Height * 0.7d);
+            }
+
+            _handle = XCreateWindow(_x11.Display, _x11.RootWindow, 10, 10, defaultWidth, defaultHeight, 0,
                 depth,
                 (int)CreateWindowArgs.InputOutput, 
                 visual,
                 new UIntPtr((uint)valueMask), ref attr);
 
             if (_useRenderWindow)
-                _renderHandle = XCreateWindow(_x11.Display, _handle, 0, 0, 300, 200, 0, depth,
+                _renderHandle = XCreateWindow(_x11.Display, _handle, 0, 0, defaultWidth, defaultHeight, 0, depth,
                     (int)CreateWindowArgs.InputOutput,
                     visual,
                     new UIntPtr((uint)(SetWindowValuemask.BorderPixel | SetWindowValuemask.BitGravity |
diff --git a/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/DynamicResourceExtension.cs b/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/DynamicResourceExtension.cs
index 0a9289bec9..5bdb0cc235 100644
--- a/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/DynamicResourceExtension.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/DynamicResourceExtension.cs
@@ -18,7 +18,7 @@ namespace Avalonia.Markup.Xaml.MarkupExtensions
         {
         }
 
-        public DynamicResourceExtension(string resourceKey)
+        public DynamicResourceExtension(object resourceKey)
         {
             ResourceKey = resourceKey;
         }
diff --git a/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/StaticResourceExtension.cs b/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/StaticResourceExtension.cs
index d6b170ae9d..6d055e033f 100644
--- a/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/StaticResourceExtension.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/StaticResourceExtension.cs
@@ -16,12 +16,12 @@ namespace Avalonia.Markup.Xaml.MarkupExtensions
         {
         }
 
-        public StaticResourceExtension(string resourceKey)
+        public StaticResourceExtension(object resourceKey)
         {
             ResourceKey = resourceKey;
         }
 
-        public string ResourceKey { get; set; }
+        public object ResourceKey { get; set; }
 
         public object ProvideValue(IServiceProvider serviceProvider)
         {
diff --git a/src/Shared/PlatformSupport/AssetLoader.cs b/src/Shared/PlatformSupport/AssetLoader.cs
index 9d921acde6..dd72934560 100644
--- a/src/Shared/PlatformSupport/AssetLoader.cs
+++ b/src/Shared/PlatformSupport/AssetLoader.cs
@@ -242,6 +242,7 @@ namespace Avalonia.Shared.PlatformSupport
                     throw new InvalidOperationException(
                         $"Assembly {name} needs to be referenced and explicitly loaded before loading resources");
 #else
+                    name = Uri.UnescapeDataString(name);
                     AssemblyNameCache[name] = rv = new AssemblyDescriptor(Assembly.Load(name));
 #endif
                 }
diff --git a/src/Windows/Avalonia.Win32/ScreenImpl.cs b/src/Windows/Avalonia.Win32/ScreenImpl.cs
index 1833e21e23..e77aa07bcd 100644
--- a/src/Windows/Avalonia.Win32/ScreenImpl.cs
+++ b/src/Windows/Avalonia.Win32/ScreenImpl.cs
@@ -30,6 +30,8 @@ namespace Avalonia.Win32
                             MONITORINFO monitorInfo = MONITORINFO.Create();
                             if (GetMonitorInfo(monitor,ref monitorInfo))
                             {
+                                GetDpiForMonitor(monitor, MONITOR_DPI_TYPE.MDT_EFFECTIVE_DPI, out var x, out _);
+
                                 RECT bounds = monitorInfo.rcMonitor;
                                 RECT workingArea = monitorInfo.rcWork;
                                 PixelRect avaloniaBounds = new PixelRect(bounds.left, bounds.top, bounds.right - bounds.left,
@@ -38,7 +40,7 @@ namespace Avalonia.Win32
                                     new PixelRect(workingArea.left, workingArea.top, workingArea.right - workingArea.left,
                                         workingArea.bottom - workingArea.top);
                                 screens[index] =
-                                    new WinScreen(avaloniaBounds, avaloniaWorkArea, monitorInfo.dwFlags == 1,
+                                    new WinScreen((double)x / 96.0d, avaloniaBounds, avaloniaWorkArea, monitorInfo.dwFlags == 1,
                                         monitor);
                                 index++;
                             }
diff --git a/src/Windows/Avalonia.Win32/WinScreen.cs b/src/Windows/Avalonia.Win32/WinScreen.cs
index e849800e62..0cf9fe31db 100644
--- a/src/Windows/Avalonia.Win32/WinScreen.cs
+++ b/src/Windows/Avalonia.Win32/WinScreen.cs
@@ -7,7 +7,7 @@ namespace Avalonia.Win32
     {
         private readonly IntPtr _hMonitor;
 
-        public WinScreen(PixelRect bounds, PixelRect workingArea, bool primary, IntPtr hMonitor) : base(bounds, workingArea, primary)
+        public WinScreen(double pixelDensity, PixelRect bounds, PixelRect workingArea, bool primary, IntPtr hMonitor) : base(pixelDensity, bounds, workingArea, primary)
         {
             this._hMonitor = hMonitor;
         }
diff --git a/tests/Avalonia.Controls.UnitTests/ContextMenuTests.cs b/tests/Avalonia.Controls.UnitTests/ContextMenuTests.cs
index ac80fc6c7a..f44f89e91f 100644
--- a/tests/Avalonia.Controls.UnitTests/ContextMenuTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ContextMenuTests.cs
@@ -198,7 +198,7 @@ namespace Avalonia.Controls.UnitTests
             var screen = new PixelRect(new PixelPoint(), new PixelSize(100, 100));
             var screenImpl = new Mock<IScreenImpl>();
             screenImpl.Setup(x => x.ScreenCount).Returns(1);
-            screenImpl.Setup(X => X.AllScreens).Returns( new[] { new Screen(screen, screen, true) });
+            screenImpl.Setup(X => X.AllScreens).Returns( new[] { new Screen(1, screen, screen, true) });
 
             popupImpl = MockWindowingPlatform.CreatePopupMock();
             popupImpl.SetupGet(x => x.Scaling).Returns(1);
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs
index 4e4d92afdc..8f27ebe853 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs
@@ -109,6 +109,28 @@ namespace Avalonia.Controls.UnitTests.Primitives
             Assert.True(items[1].IsSelected);
         }
 
+        [Fact]
+        public void Setting_SelectedIndex_During_Initialize_Should_Select_Item_When_AlwaysSelected_Is_Used()
+        {
+            var listBox = new ListBox
+            {
+                SelectionMode = SelectionMode.Single | SelectionMode.AlwaysSelected
+            };
+
+            listBox.BeginInit();
+
+            listBox.SelectedIndex = 1;
+            var items = new AvaloniaList<string>();
+            listBox.Items = items;
+            items.Add("A");
+            items.Add("B");
+            items.Add("C");
+
+            listBox.EndInit();
+
+            Assert.Equal("B", listBox.SelectedItem);
+        }
+
         [Fact]
         public void Setting_SelectedIndex_Before_ApplyTemplate_Should_Set_Item_IsSelected_True()
         {
diff --git a/tests/Avalonia.Controls.UnitTests/WindowTests.cs b/tests/Avalonia.Controls.UnitTests/WindowTests.cs
index 75239f014f..d87014f646 100644
--- a/tests/Avalonia.Controls.UnitTests/WindowTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/WindowTests.cs
@@ -271,8 +271,8 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Window_Should_Be_Centered_When_WindowStartupLocation_Is_CenterScreen()
         {
-            var screen1 = new Mock<Screen>(new PixelRect(new PixelSize(1920, 1080)), new PixelRect(new PixelSize(1920, 1040)), true);
-            var screen2 = new Mock<Screen>(new PixelRect(new PixelSize(1366, 768)), new PixelRect(new PixelSize(1366, 728)), false);
+            var screen1 = new Mock<Screen>(1.0, new PixelRect(new PixelSize(1920, 1080)), new PixelRect(new PixelSize(1920, 1040)), true);
+            var screen2 = new Mock<Screen>(1.0, new PixelRect(new PixelSize(1366, 768)), new PixelRect(new PixelSize(1366, 728)), false);
 
             var screens = new Mock<IScreenImpl>();
             screens.Setup(x => x.AllScreens).Returns(new Screen[] { screen1.Object, screen2.Object });
diff --git a/tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs b/tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs
index a0511761e4..fd93df46b8 100644
--- a/tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs
@@ -93,5 +93,29 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(new Rect(0, 0, 100, 50), target.Children[0].Bounds);
             Assert.Equal(new Rect(100, 0, 100, 50), target.Children[1].Bounds);
         }
+
+        [Fact]
+        public void Applies_ItemWidth_And_ItemHeight_Properties()
+        {
+            var target = new WrapPanel()
+                        {
+                            Orientation = Orientation.Horizontal,
+                            Width = 50,
+                            ItemWidth = 20,
+                            ItemHeight = 15,
+                            Children =
+                            {
+                                new Border(),
+                                new Border(),
+                            }
+                        };
+
+            target.Measure(Size.Infinity);
+            target.Arrange(new Rect(target.DesiredSize));
+
+            Assert.Equal(new Size(50, 15), target.Bounds.Size);
+            Assert.Equal(new Rect(0, 0, 20, 15), target.Children[0].Bounds);
+            Assert.Equal(new Rect(20, 0, 20, 15), target.Children[1].Bounds);
+        }
     }
 }
diff --git a/tests/Avalonia.Markup.UnitTests/Data/BindingTests.cs b/tests/Avalonia.Markup.UnitTests/Data/BindingTests.cs
index 0ba06980af..7e053392c7 100644
--- a/tests/Avalonia.Markup.UnitTests/Data/BindingTests.cs
+++ b/tests/Avalonia.Markup.UnitTests/Data/BindingTests.cs
@@ -154,6 +154,18 @@ namespace Avalonia.Markup.UnitTests.Data
             Assert.Equal("bar", source.Foo);
         }
 
+        [Fact]
+        public void OneTime_Binding_Releases_Subscription_If_DataContext_Set_Later()
+        {
+            var target = new TextBlock();
+            var source = new Source { Foo = "foo" };
+
+            target.Bind(TextBlock.TextProperty, new Binding("Foo", BindingMode.OneTime));
+            target.DataContext = source;
+
+            Assert.Equal(0, source.SubscriberCount);
+        }
+
         [Fact]
         public void OneWayToSource_Binding_Should_Be_Set_Up()
         {
@@ -196,6 +208,30 @@ namespace Avalonia.Markup.UnitTests.Data
             Assert.Equal("baz", target.Text);
         }
 
+        [Fact]
+        public void OneWayToSource_Binding_Should_Not_StackOverflow_With_Null_Value()
+        {
+            // Issue #2912
+            var target = new TextBlock { Text = null };
+            var binding = new Binding
+            {
+                Path = "Foo",
+                Mode = BindingMode.OneWayToSource,
+            };
+
+            target.Bind(TextBox.TextProperty, binding);
+
+            var source = new Source { Foo = "foo" };
+            target.DataContext = source;
+
+            Assert.Null(source.Foo);
+
+            // When running tests under NCrunch, NCrunch replaces the standard StackOverflowException
+            // with its own, which will be caught by our code. Detect the stackoverflow anyway, by
+            // making sure the target property was only set once.
+            Assert.Equal(2, source.FooSetCount);
+        }
+
         [Fact]
         public void Default_BindingMode_Should_Be_Used()
         {
@@ -543,6 +579,23 @@ namespace Avalonia.Markup.UnitTests.Data
             Assert.Equal(expected, child.DoubleValue);
         }
 
+        [Fact]
+        public void Combined_OneTime_And_OneWayToSource_Bindings_Should_Release_Subscriptions()
+        {
+            var target1 = new TextBlock();
+            var target2 = new TextBlock();
+            var root = new Panel { Children = { target1, target2 } };
+            var source = new Source { Foo = "foo" };
+
+            using (target1.Bind(TextBlock.TextProperty, new Binding("Foo", BindingMode.OneTime)))
+            using (target2.Bind(TextBlock.TextProperty, new Binding("Foo", BindingMode.OneWayToSource)))
+            {
+                root.DataContext = source;
+            }
+
+            Assert.Equal(0, source.SubscriberCount);
+        }
+
         private class StyledPropertyClass : AvaloniaObject
         {
             public static readonly StyledProperty<double> DoubleValueProperty =
@@ -622,6 +675,7 @@ namespace Avalonia.Markup.UnitTests.Data
 
         public class Source : INotifyPropertyChanged
         {
+            private PropertyChangedEventHandler _propertyChanged;
             private string _foo;
 
             public string Foo
@@ -630,15 +684,25 @@ namespace Avalonia.Markup.UnitTests.Data
                 set
                 {
                     _foo = value;
+                    ++FooSetCount;
                     RaisePropertyChanged();
                 }
             }
 
-            public event PropertyChangedEventHandler PropertyChanged;
+            public int FooSetCount { get; private set; }
+
+
+            public int SubscriberCount { get; private set; }
+
+            public event PropertyChangedEventHandler PropertyChanged
+            {
+                add { _propertyChanged += value; ++SubscriberCount; }
+                remove { _propertyChanged += value; --SubscriberCount; }
+            }
 
             private void RaisePropertyChanged([CallerMemberName] string prop = "")
             {
-                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(prop));
+                _propertyChanged?.Invoke(this, new PropertyChangedEventArgs(prop));
             }
         }
 
diff --git a/tests/Avalonia.Markup.UnitTests/Parsers/ExpressionObserverBuilderTests_AttachedProperty.cs b/tests/Avalonia.Markup.UnitTests/Parsers/ExpressionObserverBuilderTests_AttachedProperty.cs
index 5b97ab7ae6..ff9e259eab 100644
--- a/tests/Avalonia.Markup.UnitTests/Parsers/ExpressionObserverBuilderTests_AttachedProperty.cs
+++ b/tests/Avalonia.Markup.UnitTests/Parsers/ExpressionObserverBuilderTests_AttachedProperty.cs
@@ -120,6 +120,8 @@ namespace Avalonia.Markup.UnitTests.Parsers
             var result = run();
             result.Item1.Subscribe(x => { });
 
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
             GC.Collect();
 
             Assert.Null(result.Item2.Target);
diff --git a/tests/Avalonia.ReactiveUI.UnitTests/AvaloniaActivationForViewFetcherTest.cs b/tests/Avalonia.ReactiveUI.UnitTests/AvaloniaActivationForViewFetcherTest.cs
index 1d85312b1a..643dd3efac 100644
--- a/tests/Avalonia.ReactiveUI.UnitTests/AvaloniaActivationForViewFetcherTest.cs
+++ b/tests/Avalonia.ReactiveUI.UnitTests/AvaloniaActivationForViewFetcherTest.cs
@@ -20,9 +20,9 @@ namespace Avalonia.ReactiveUI.UnitTests
 {
     public class AvaloniaActivationForViewFetcherTest
     {
-        public class TestUserControl : UserControl, IActivatable { }
+        public class TestUserControl : UserControl, IActivatableView { }
 
-        public class TestUserControlWithWhenActivated : UserControl, IActivatable
+        public class TestUserControlWithWhenActivated : UserControl, IActivatableView
         {
             public bool Active { get; private set; }
 
@@ -38,7 +38,7 @@ namespace Avalonia.ReactiveUI.UnitTests
             }
         }
 
-        public class TestWindowWithWhenActivated : Window, IActivatable
+        public class TestWindowWithWhenActivated : Window, IActivatableView
         {
             public bool Active { get; private set; }
 
@@ -54,7 +54,7 @@ namespace Avalonia.ReactiveUI.UnitTests
             }
         }
 
-        public class ActivatableViewModel : ISupportsActivation
+        public class ActivatableViewModel : IActivatableViewModel
         {
             public ViewModelActivator Activator { get; }
 
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs
index 4c302a24a2..b4743e900d 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs
@@ -96,6 +96,55 @@ namespace Avalonia.Visuals.UnitTests.Rendering
             Assert.Equal(new List<IVisual> { root, decorator, border, canvas }, result);
         }
 
+        [Fact]
+        public void Should_Add_Dirty_Rect_On_Child_Remove()
+        {
+            var dispatcher = new ImmediateDispatcher();
+            var loop = new Mock<IRenderLoop>();
+
+            Decorator decorator;
+            Border border;
+            var root = new TestRoot
+            {
+                Width = 100,
+                Height= 100,
+                Child = decorator = new Decorator
+                {
+                    Child = border = new Border
+                    {
+                        Width = 50,
+                        Height = 50,
+                        Background = Brushes.Red,
+                    },
+                }
+            };
+
+            root.Measure(Size.Infinity);
+            root.Arrange(new Rect(root.DesiredSize));
+
+            var sceneBuilder = new SceneBuilder();
+            var target = new DeferredRenderer(
+                root,
+                loop.Object,
+                sceneBuilder: sceneBuilder,
+                dispatcher: dispatcher);
+
+            root.Renderer = target;
+            target.Start();
+            RunFrame(target);
+
+            decorator.Child = null;
+
+            RunFrame(target);
+
+            var scene = target.UnitTestScene();
+            var stackNode = scene.FindNode(decorator);
+            var dirty = scene.Layers[0].Dirty.ToList();
+
+            Assert.Equal(1, dirty.Count);
+            Assert.Equal(new Rect(25, 25, 50, 50), dirty[0]);
+        }
+
         [Fact]
         public void Should_Update_VisualNode_Order_On_Child_Remove_Insert()
         {
@@ -270,6 +319,56 @@ namespace Avalonia.Visuals.UnitTests.Rendering
             Assert.Same(stackNode.Children[1].Visual, canvas1);
         }
 
+        [Fact]
+        public void Should_Update_VisualNodes_When_Child_Moved_To_New_Parent()
+        {
+            var dispatcher = new ImmediateDispatcher();
+            var loop = new Mock<IRenderLoop>();
+
+            Decorator moveFrom;
+            Decorator moveTo;
+            Canvas moveMe;
+            var root = new TestRoot
+            {
+                Child = new StackPanel
+                {
+                    Children =
+                    {
+                        (moveFrom = new Decorator
+                        {
+                            Child = moveMe = new Canvas(),
+                        }),
+                        (moveTo = new Decorator()),
+                    }
+                }
+            };
+
+            var sceneBuilder = new SceneBuilder();
+            var target = new DeferredRenderer(
+                root,
+                loop.Object,
+                sceneBuilder: sceneBuilder,
+                dispatcher: dispatcher);
+
+            root.Renderer = target;
+            target.Start();
+            RunFrame(target);
+
+            moveFrom.Child = null;
+            moveTo.Child = moveMe;
+
+            RunFrame(target);
+
+            var scene = target.UnitTestScene();
+            var moveFromNode = (VisualNode)scene.FindNode(moveFrom);
+            var moveToNode = (VisualNode)scene.FindNode(moveTo);
+
+            Assert.Empty(moveFromNode.Children);
+            Assert.Equal(1, moveToNode.Children.Count);
+            Assert.Same(moveMe, moveToNode.Children[0].Visual);
+
+        }
+
         [Fact]
         public void Should_Push_Opacity_For_Controls_With_Less_Than_1_Opacity()
         {
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests.cs
index 3d084b81e1..13bcd27240 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests.cs
@@ -475,6 +475,64 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
             }
         }
 
+        [Fact]
+        public void Should_Update_When_Control_Moved()
+        {
+            using (UnitTestApplication.Start(TestServices.MockPlatformRenderInterface))
+            {
+                Decorator moveFrom;
+                Decorator moveTo;
+                Canvas moveMe;
+                var tree = new TestRoot
+                {
+                    Width = 100,
+                    Height = 100,
+                    Child = new StackPanel
+                    {
+                        Children =
+                        {
+                            (moveFrom = new Decorator
+                            {
+                                Child = moveMe = new Canvas(),
+                            }),
+                            (moveTo = new Decorator()),
+                        }
+                    }
+                };
+
+                tree.Measure(Size.Infinity);
+                tree.Arrange(new Rect(tree.DesiredSize));
+
+                var scene = new Scene(tree);
+                var sceneBuilder = new SceneBuilder();
+                sceneBuilder.UpdateAll(scene);
+
+                var moveFromNode = (VisualNode)scene.FindNode(moveFrom);
+                var moveToNode = (VisualNode)scene.FindNode(moveTo);
+
+                Assert.Equal(1, moveFromNode.Children.Count);
+                Assert.Same(moveMe, moveFromNode.Children[0].Visual);
+                Assert.Empty(moveToNode.Children);
+
+                moveFrom.Child = null;
+                moveTo.Child = moveMe;
+
+                scene = scene.CloneScene();
+                moveFromNode = (VisualNode)scene.FindNode(moveFrom);
+                moveToNode = (VisualNode)scene.FindNode(moveTo);
+
+                moveFromNode.SortChildren(scene);
+                moveToNode.SortChildren(scene);
+                sceneBuilder.Update(scene, moveFrom);
+                sceneBuilder.Update(scene, moveTo);
+                sceneBuilder.Update(scene, moveMe);
+
+                Assert.Empty(moveFromNode.Children);
+                Assert.Equal(1, moveToNode.Children.Count);
+                Assert.Same(moveMe, moveToNode.Children[0].Visual);
+            }
+        }
+
         [Fact]
         public void Should_Update_When_Control_Made_Invisible()
         {