diff --git a/src/Avalonia.Animation/Animation.cs b/src/Avalonia.Animation/Animation.cs
index daa4793ef0..172782c5a9 100644
--- a/src/Avalonia.Animation/Animation.cs
+++ b/src/Avalonia.Animation/Animation.cs
@@ -3,10 +3,11 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Reactive.Disposables;
 using System.Reactive.Linq;
+using System.Threading;
 using System.Threading.Tasks;
+
 using Avalonia.Animation.Animators;
 using Avalonia.Animation.Easings;
-using Avalonia.Collections;
 using Avalonia.Data;
 using Avalonia.Metadata;
 
@@ -319,7 +320,7 @@ namespace Avalonia.Animation
             return (newAnimatorInstances, subscriptions);
         }
 
-        /// <inheritdocs/>
+        /// <inheritdoc/>
         public IDisposable Apply(Animatable control, IClock clock, IObservable<bool> match, Action onComplete)
         {
             var (animators, subscriptions) = InterpretKeyframes(control);
@@ -344,25 +345,40 @@ namespace Avalonia.Animation
 
                 if (onComplete != null)
                 {
-                    Task.WhenAll(completionTasks).ContinueWith(_ => onComplete());
+                    Task.WhenAll(completionTasks).ContinueWith(
+                        (_, state) => ((Action)state).Invoke(),
+                        onComplete);
                 }
             }
             return new CompositeDisposable(subscriptions);
         }
 
-        /// <inheritdocs/>
-        public Task RunAsync(Animatable control, IClock clock = null)
+        /// <inheritdoc/>
+        public Task RunAsync(Animatable control, IClock clock = null, CancellationToken cancellationToken = default)
         {
+            if (cancellationToken.IsCancellationRequested)
+            {
+                return Task.CompletedTask;
+            }
+
             var run = new TaskCompletionSource<object>();
 
             if (this.IterationCount == IterationCount.Infinite)
                 run.SetException(new InvalidOperationException("Looping animations must not use the Run method."));
 
-            IDisposable subscriptions = null;
+            IDisposable subscriptions = null, cancellation = null;
             subscriptions = this.Apply(control, clock, Observable.Return(true), () =>
             {
-                run.SetResult(null);
+                run.TrySetResult(null);
+                subscriptions?.Dispose();
+                cancellation?.Dispose();
+            });
+
+            cancellation = cancellationToken.Register(() =>
+            {
+                run.TrySetResult(null);
                 subscriptions?.Dispose();
+                cancellation?.Dispose();
             });
 
             return run.Task;
diff --git a/src/Avalonia.Animation/AnimationInstance`1.cs b/src/Avalonia.Animation/AnimationInstance`1.cs
index 0e1882ce75..cf79640150 100644
--- a/src/Avalonia.Animation/AnimationInstance`1.cs
+++ b/src/Avalonia.Animation/AnimationInstance`1.cs
@@ -37,6 +37,7 @@ namespace Avalonia.Animation
         private IDisposable _timerSub;
         private readonly IClock _baseClock;
         private IClock _clock;
+        private EventHandler<AvaloniaPropertyChangedEventArgs> _propertyChangedDelegate;
 
         public AnimationInstance(Animation animation, Animatable control, Animator<T> animator, IClock baseClock, Action OnComplete, Func<double, T, T> Interpolator)
         {
@@ -46,9 +47,6 @@ namespace Avalonia.Animation
             _onCompleteAction = OnComplete;
             _interpolator = Interpolator;
             _baseClock = baseClock;
-            control.PropertyChanged += ControlPropertyChanged;
-
-            UpdateNeutralValue();
             FetchProperties();
         }
 
@@ -82,6 +80,7 @@ namespace Avalonia.Animation
             // Animation may have been stopped before it has finished.
             ApplyFinalFill();
 
+            _targetControl.PropertyChanged -= _propertyChangedDelegate;
             _timerSub?.Dispose();
             _clock.PlayState = PlayState.Stop;
         }
@@ -90,6 +89,9 @@ namespace Avalonia.Animation
         {
             _clock = new Clock(_baseClock);
             _timerSub = _clock.Subscribe(Step);
+            _propertyChangedDelegate ??= ControlPropertyChanged;
+            _targetControl.PropertyChanged += _propertyChangedDelegate;
+            UpdateNeutralValue();
         }
 
         public void Step(TimeSpan frameTick)
diff --git a/src/Avalonia.Animation/ApiCompatBaseline.txt b/src/Avalonia.Animation/ApiCompatBaseline.txt
new file mode 100644
index 0000000000..58cb7830e7
--- /dev/null
+++ b/src/Avalonia.Animation/ApiCompatBaseline.txt
@@ -0,0 +1,6 @@
+Compat issues with assembly Avalonia.Animation:
+MembersMustExist : Member 'public System.Threading.Tasks.Task Avalonia.Animation.Animation.RunAsync(Avalonia.Animation.Animatable, Avalonia.Animation.IClock)' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Threading.Tasks.Task Avalonia.Animation.IAnimation.RunAsync(Avalonia.Animation.Animatable, Avalonia.Animation.IClock)' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public System.Threading.Tasks.Task Avalonia.Animation.IAnimation.RunAsync(Avalonia.Animation.Animatable, Avalonia.Animation.IClock)' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Threading.Tasks.Task Avalonia.Animation.IAnimation.RunAsync(Avalonia.Animation.Animatable, Avalonia.Animation.IClock, System.Threading.CancellationToken)' is present in the implementation but not in the contract.
+Total Issues: 4
diff --git a/src/Avalonia.Animation/IAnimation.cs b/src/Avalonia.Animation/IAnimation.cs
index ff85535d8a..d037834630 100644
--- a/src/Avalonia.Animation/IAnimation.cs
+++ b/src/Avalonia.Animation/IAnimation.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Avalonia.Animation
@@ -16,6 +17,6 @@ namespace Avalonia.Animation
         /// <summary>
         /// Run the animation on the specified control.
         /// </summary>
-        Task RunAsync(Animatable control, IClock clock);
+        Task RunAsync(Animatable control, IClock clock, CancellationToken cancellationToken = default);
     }
 }
diff --git a/src/Avalonia.Controls.DataGrid/DataGrid.cs b/src/Avalonia.Controls.DataGrid/DataGrid.cs
index 1b4632d368..83f13fe199 100644
--- a/src/Avalonia.Controls.DataGrid/DataGrid.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGrid.cs
@@ -75,7 +75,6 @@ namespace Avalonia.Controls
         private const double DATAGRID_defaultMinColumnWidth = 20;
         private const double DATAGRID_defaultMaxColumnWidth = double.PositiveInfinity;
 
-        private List<Exception> _validationErrors;
         private List<Exception> _bindingValidationErrors;
         private IDisposable _validationSubscription;
 
@@ -102,7 +101,6 @@ namespace Avalonia.Controls
         private bool _areHandlersSuspended;
         private bool _autoSizingColumns;
         private IndexToValueTable<bool> _collapsedSlotsTable;
-        private DataGridCellCoordinates _currentCellCoordinates;
         private Control _clickedElement;
 
         // used to store the current column during a Reset
@@ -141,7 +139,6 @@ namespace Avalonia.Controls
         private DataGridSelectedItemsCollection _selectedItems;
         private bool _temporarilyResetCurrentCell;
         private object _uneditedValue; // Represents the original current cell value at the time it enters editing mode.
-        private ICellEditBinding _currentCellEditBinding;
 
         // An approximation of the sum of the heights in pixels of the scrolling rows preceding
         // the first displayed scrolling row.  Since the scrolled off rows are discarded, the grid
diff --git a/src/Avalonia.Controls.DataGrid/DataGridRows.cs b/src/Avalonia.Controls.DataGrid/DataGridRows.cs
index a69b8eafe1..4bfbd7d818 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridRows.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridRows.cs
@@ -425,7 +425,7 @@ namespace Avalonia.Controls
                 UpdateDisplayedRows(DisplayData.FirstScrollingSlot, CellsHeight);
             }
 
-            if (DisplayData.FirstScrollingSlot < slot && DisplayData.LastScrollingSlot > slot)
+            if (DisplayData.FirstScrollingSlot < slot && (DisplayData.LastScrollingSlot > slot || DisplayData.LastScrollingSlot == -1))
             {
                 // The row is already displayed in its entirety
                 return true;
diff --git a/src/Avalonia.Controls/Application.cs b/src/Avalonia.Controls/Application.cs
index 54c576bb76..157bebe02b 100644
--- a/src/Avalonia.Controls/Application.cs
+++ b/src/Avalonia.Controls/Application.cs
@@ -13,6 +13,7 @@ using Avalonia.Platform;
 using Avalonia.Rendering;
 using Avalonia.Styling;
 using Avalonia.Threading;
+#nullable enable
 
 namespace Avalonia
 {
@@ -35,27 +36,27 @@ namespace Avalonia
         /// <summary>
         /// The application-global data templates.
         /// </summary>
-        private DataTemplates _dataTemplates;
+        private DataTemplates? _dataTemplates;
 
         private readonly Lazy<IClipboard> _clipboard =
             new Lazy<IClipboard>(() => (IClipboard)AvaloniaLocator.Current.GetService(typeof(IClipboard)));
         private readonly Styler _styler = new Styler();
-        private Styles _styles;
-        private IResourceDictionary _resources;
+        private Styles? _styles;
+        private IResourceDictionary? _resources;
         private bool _notifyingResourcesChanged;
-        private Action<IReadOnlyList<IStyle>> _stylesAdded;
-        private Action<IReadOnlyList<IStyle>> _stylesRemoved;
+        private Action<IReadOnlyList<IStyle>>? _stylesAdded;
+        private Action<IReadOnlyList<IStyle>>? _stylesRemoved;
 
         /// <summary>
         /// Defines the <see cref="DataContext"/> property.
         /// </summary>
-        public static readonly StyledProperty<object> DataContextProperty =
+        public static readonly StyledProperty<object?> DataContextProperty =
             StyledElement.DataContextProperty.AddOwner<Application>();
 
         /// <inheritdoc/>
-        public event EventHandler<ResourcesChangedEventArgs> ResourcesChanged;
+        public event EventHandler<ResourcesChangedEventArgs>? ResourcesChanged;
 
-        public event EventHandler<UrlOpenedEventArgs> UrlsOpened; 
+        public event EventHandler<UrlOpenedEventArgs>? UrlsOpened; 
 
         /// <summary>
         /// Creates an instance of the <see cref="Application"/> class.
@@ -72,7 +73,7 @@ namespace Avalonia
         /// The data context property specifies the default object that will
         /// be used for data binding.
         /// </remarks>
-        public object DataContext
+        public object? DataContext
         {
             get { return GetValue(DataContextProperty); }
             set { SetValue(DataContextProperty, value); }
@@ -162,7 +163,7 @@ namespace Avalonia
         /// <summary>
         /// Gets the styling parent of the application, which is null.
         /// </summary>
-        IStyleHost IStyleHost.StylingParent => null;
+        IStyleHost? IStyleHost.StylingParent => null;
 
         /// <inheritdoc/>
         bool IStyleHost.IsStylesInitialized => _styles != null;
@@ -194,7 +195,7 @@ namespace Avalonia
         public virtual void Initialize() { }
 
         /// <inheritdoc/>
-        bool IResourceNode.TryGetResource(object key, out object value)
+        bool IResourceNode.TryGetResource(object key, out object? value)
         {
             value = null;
             return (_resources?.TryGetResource(key, out value) ?? false) ||
@@ -279,17 +280,17 @@ namespace Avalonia
             NotifyResourcesChanged(e);
         }
 
-        private string _name;
+        private string? _name;
         /// <summary>
         /// Defines Name property
         /// </summary>
-        public static readonly DirectProperty<Application, string> NameProperty =
-            AvaloniaProperty.RegisterDirect<Application, string>("Name", o => o.Name, (o, v) => o.Name = v);
+        public static readonly DirectProperty<Application, string?> NameProperty =
+            AvaloniaProperty.RegisterDirect<Application, string?>("Name", o => o.Name, (o, v) => o.Name = v);
 
         /// <summary>
         /// Application name to be used for various platform-specific purposes
         /// </summary>
-        public string Name
+        public string? Name
         {
             get => _name;
             set => SetAndRaise(NameProperty, ref _name, value);
diff --git a/src/Avalonia.Controls/ComboBox.cs b/src/Avalonia.Controls/ComboBox.cs
index f8728af87f..dd2109e6cd 100644
--- a/src/Avalonia.Controls/ComboBox.cs
+++ b/src/Avalonia.Controls/ComboBox.cs
@@ -205,7 +205,7 @@ namespace Avalonia.Controls
             if (e.Handled)
                 return;
 
-            if (e.Key == Key.F4 ||
+            if ((e.Key == Key.F4 && e.KeyModifiers.HasAllFlags(KeyModifiers.Alt) == false) ||
                 ((e.Key == Key.Down || e.Key == Key.Up) && e.KeyModifiers.HasAllFlags(KeyModifiers.Alt)))
             {
                 IsDropDownOpen = !IsDropDownOpen;
diff --git a/src/Avalonia.Controls/Expander.cs b/src/Avalonia.Controls/Expander.cs
index 052b42a233..b9c79e5749 100644
--- a/src/Avalonia.Controls/Expander.cs
+++ b/src/Avalonia.Controls/Expander.cs
@@ -1,7 +1,11 @@
+using System.Threading;
+
 using Avalonia.Animation;
 using Avalonia.Controls.Metadata;
 using Avalonia.Controls.Primitives;
 
+#nullable enable
+
 namespace Avalonia.Controls
 {
     /// <summary>
@@ -36,8 +40,8 @@ namespace Avalonia.Controls
     [PseudoClasses(":expanded", ":up", ":down", ":left", ":right")]
     public class Expander : HeaderedContentControl
     {
-        public static readonly StyledProperty<IPageTransition> ContentTransitionProperty =
-            AvaloniaProperty.Register<Expander, IPageTransition>(nameof(ContentTransition));
+        public static readonly StyledProperty<IPageTransition?> ContentTransitionProperty =
+            AvaloniaProperty.Register<Expander, IPageTransition?>(nameof(ContentTransition));
 
         public static readonly StyledProperty<ExpandDirection> ExpandDirectionProperty =
             AvaloniaProperty.Register<Expander, ExpandDirection>(nameof(ExpandDirection), ExpandDirection.Down);
@@ -50,6 +54,7 @@ namespace Avalonia.Controls
                 defaultBindingMode: Data.BindingMode.TwoWay);
 
         private bool _isExpanded;
+        private CancellationTokenSource? _lastTransitionCts;
 
         static Expander()
         {
@@ -61,7 +66,7 @@ namespace Avalonia.Controls
             UpdatePseudoClasses(ExpandDirection);
         }
 
-        public IPageTransition ContentTransition
+        public IPageTransition? ContentTransition
         {
             get => GetValue(ContentTransitionProperty);
             set => SetValue(ContentTransitionProperty, value);
@@ -83,19 +88,23 @@ namespace Avalonia.Controls
             }
         }
 
-        protected virtual void OnIsExpandedChanged(AvaloniaPropertyChangedEventArgs e)
+        protected virtual async void OnIsExpandedChanged(AvaloniaPropertyChangedEventArgs e)
         {
             if (Content != null && ContentTransition != null && Presenter is Visual visualContent)
             {
                 bool forward = ExpandDirection == ExpandDirection.Left ||
                                 ExpandDirection == ExpandDirection.Up;
+
+                _lastTransitionCts?.Cancel();
+                _lastTransitionCts = new CancellationTokenSource();
+
                 if (IsExpanded)
                 {
-                    ContentTransition.Start(null, visualContent, forward);
+                    await ContentTransition.Start(null, visualContent, forward, _lastTransitionCts.Token);
                 }
                 else
                 {
-                    ContentTransition.Start(visualContent, null, !forward);
+                    await ContentTransition.Start(visualContent, null, forward, _lastTransitionCts.Token);
                 }
             }
         }
diff --git a/src/Avalonia.Controls/Flyouts/FlyoutBase.cs b/src/Avalonia.Controls/Flyouts/FlyoutBase.cs
index 4725d17d65..e4b68c62fd 100644
--- a/src/Avalonia.Controls/Flyouts/FlyoutBase.cs
+++ b/src/Avalonia.Controls/Flyouts/FlyoutBase.cs
@@ -4,6 +4,7 @@ using Avalonia.Input;
 using Avalonia.Input.Raw;
 using Avalonia.Layout;
 using Avalonia.Logging;
+using Avalonia.Rendering;
 
 #nullable enable
 
@@ -51,8 +52,9 @@ namespace Avalonia.Controls.Primitives
         private bool _isOpen;
         private Control? _target;
         private FlyoutShowMode _showMode = FlyoutShowMode.Standard;
-        private Rect? enlargedPopupRect;
-        private IDisposable? transientDisposable;
+        private Rect? _enlargedPopupRect;
+        private PixelRect? _enlargePopupRectScreenPixelRect;
+        private IDisposable? _transientDisposable;
 
         protected Popup? Popup { get; private set; }
 
@@ -163,8 +165,10 @@ namespace Avalonia.Controls.Primitives
             Popup.IsOpen = false;
 
             // Ensure this isn't active
-            transientDisposable?.Dispose();
-            transientDisposable = null;
+            _transientDisposable?.Dispose();
+            _transientDisposable = null;
+            _enlargedPopupRect = null;
+            _enlargePopupRectScreenPixelRect = null;
 
             OnClosed();
         }
@@ -230,7 +234,7 @@ namespace Avalonia.Controls.Primitives
             }
             else if (ShowMode == FlyoutShowMode.TransientWithDismissOnPointerMoveAway)
             {
-                transientDisposable = InputManager.Instance?.Process.Subscribe(HandleTransientDismiss);
+                _transientDisposable = InputManager.Instance?.Process.Subscribe(HandleTransientDismiss);
             }
         }
 
@@ -246,20 +250,20 @@ namespace Avalonia.Controls.Primitives
                 // For windowed popups, enlargedPopupRect is in screen coordinates,
                 // for overlay popups, its in OverlayLayer coordinates
 
-                if (enlargedPopupRect == null)
+                if (_enlargedPopupRect == null && _enlargePopupRectScreenPixelRect == null)
                 {
                     // Only do this once when the Flyout opens & cache the result
                     if (Popup?.Host is PopupRoot root)
                     { 
                         // Get the popup root bounds and convert to screen coordinates
+                        
                         var tmp = root.Bounds.Inflate(100);
-                        var scPt = root.PointToScreen(tmp.TopLeft);
-                        enlargedPopupRect = new Rect(scPt.X, scPt.Y, tmp.Width, tmp.Height);
+                        _enlargePopupRectScreenPixelRect = new PixelRect(root.PointToScreen(tmp.TopLeft), root.PointToScreen(tmp.BottomRight));
                     }
                     else if (Popup?.Host is OverlayPopupHost host)
                     {
                         // Overlay popups are in OverlayLayer coordinates, just use that
-                        enlargedPopupRect = host.Bounds.Inflate(100);
+                        _enlargedPopupRect = host.Bounds.Inflate(100);
                     }
 
                     return;
@@ -273,24 +277,18 @@ namespace Avalonia.Controls.Primitives
                     // window will not close this (as pointer events stop), which 
                     // does match UWP
                     var pt = pArgs.Root.PointToScreen(pArgs.Position);
-                    if (!enlargedPopupRect?.Contains(new Point(pt.X, pt.Y)) ?? false)
+                    if (!_enlargePopupRectScreenPixelRect?.Contains(pt) ?? false)
                     {
                         HideCore(false);
-                        enlargedPopupRect = null;
-                        transientDisposable?.Dispose();
-                        transientDisposable = null;
                     }
                 }
                 else if (Popup?.Host is OverlayPopupHost)
                 {
                     // Same as above here, but just different coordinate space
                     // so we don't need to translate
-                    if (!enlargedPopupRect?.Contains(pArgs.Position) ?? false)
+                    if (!_enlargedPopupRect?.Contains(pArgs.Position) ?? false)
                     {
                         HideCore(false);
-                        enlargedPopupRect = null;
-                        transientDisposable?.Dispose();
-                        transientDisposable = null;
                     }
                 }
             }
diff --git a/src/Avalonia.Controls/Grid.cs b/src/Avalonia.Controls/Grid.cs
index c7d598006d..a14df1eb43 100644
--- a/src/Avalonia.Controls/Grid.cs
+++ b/src/Avalonia.Controls/Grid.cs
@@ -978,6 +978,7 @@ namespace Avalonia.Controls
         /// width is not registered in columns.</param>
         /// <param name="forceInfinityV">Passed through to MeasureCell.
         /// When "true" cells' desired height is not registered in rows.</param>
+        /// <param name="hasDesiredSizeUChanged">return true when desired size has changed</param>
         private void MeasureCellsGroup(
             int cellsHead,
             Size referenceSize,
diff --git a/src/Avalonia.Controls/GridLength.cs b/src/Avalonia.Controls/GridLength.cs
index b8418949d9..ee6a146d61 100644
--- a/src/Avalonia.Controls/GridLength.cs
+++ b/src/Avalonia.Controls/GridLength.cs
@@ -77,6 +77,12 @@ namespace Avalonia.Controls
         /// </summary>
         public static GridLength Auto => new GridLength(0, GridUnitType.Auto);
 
+        /// <summary>
+        /// Gets an instance of <see cref="GridLength"/> that indicates that a row or column should
+        /// fill its content.
+        /// </summary>
+        public static GridLength Star => new GridLength(1, GridUnitType.Star);
+
         /// <summary>
         /// Gets the unit of the <see cref="GridLength"/>.
         /// </summary>
diff --git a/src/Avalonia.Controls/Menu.cs b/src/Avalonia.Controls/Menu.cs
index 4da044fec1..706be376a9 100644
--- a/src/Avalonia.Controls/Menu.cs
+++ b/src/Avalonia.Controls/Menu.cs
@@ -17,7 +17,6 @@ namespace Avalonia.Controls
         private static readonly ITemplate<IPanel> DefaultPanel =
             new FuncTemplate<IPanel>(() => new StackPanel { Orientation = Orientation.Horizontal });
 
-        private LightDismissOverlayLayer? _overlay;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="Menu"/> class.
diff --git a/src/Avalonia.Controls/MenuItem.cs b/src/Avalonia.Controls/MenuItem.cs
index 4c801c2e06..7b06d3c868 100644
--- a/src/Avalonia.Controls/MenuItem.cs
+++ b/src/Avalonia.Controls/MenuItem.cs
@@ -36,7 +36,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Defines the <see cref="HotKey"/> property.
         /// </summary>
-        public static readonly StyledProperty<KeyGesture> HotKeyProperty =
+        public static readonly StyledProperty<KeyGesture?> HotKeyProperty =
             HotKeyManager.HotKeyProperty.AddOwner<MenuItem>();
 
         /// <summary>
@@ -108,7 +108,7 @@ namespace Avalonia.Controls
         private ICommand? _command;
         private bool _commandCanExecute = true;
         private Popup? _popup;
-        private KeyGesture _hotkey;
+        private KeyGesture? _hotkey;
         private bool _isEmbeddedInMenu;
 
         /// <summary>
@@ -214,7 +214,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets an <see cref="KeyGesture"/> associated with this control
         /// </summary>
-        public KeyGesture HotKey
+        public KeyGesture? HotKey
         {
             get { return GetValue(HotKeyProperty); }
             set { SetValue(HotKeyProperty, value); }
diff --git a/src/Avalonia.Controls/Presenters/CarouselPresenter.cs b/src/Avalonia.Controls/Presenters/CarouselPresenter.cs
index 7888249bdd..81f43865a7 100644
--- a/src/Avalonia.Controls/Presenters/CarouselPresenter.cs
+++ b/src/Avalonia.Controls/Presenters/CarouselPresenter.cs
@@ -186,7 +186,7 @@ namespace Avalonia.Controls.Presenters
 
                 if (PageTransition != null && (from != null || to != null))
                 {
-                    await PageTransition.Start((Visual)from, (Visual)to, fromIndex < toIndex);
+                    await PageTransition.Start((Visual)from, (Visual)to, fromIndex < toIndex, default);
                 }
                 else if (to != null)
                 {
diff --git a/src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs b/src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs
index b0b52812b9..e3783febdd 100644
--- a/src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs
+++ b/src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs
@@ -511,8 +511,8 @@ namespace Avalonia.Controls.Presenters
             else if (scrollable.IsLogicalScrollEnabled)
             {
                 Viewport = scrollable.Viewport;
-                Extent = scrollable.Extent;
                 Offset = scrollable.Offset;
+                Extent = scrollable.Extent;
             }
         }
 
diff --git a/src/Avalonia.Controls/Primitives/AdornerLayer.cs b/src/Avalonia.Controls/Primitives/AdornerLayer.cs
index 9834bf3d3b..a397608aba 100644
--- a/src/Avalonia.Controls/Primitives/AdornerLayer.cs
+++ b/src/Avalonia.Controls/Primitives/AdornerLayer.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Specialized;
 using System.Linq;
+using System.Resources;
 using Avalonia.Media;
 using Avalonia.Rendering;
 using Avalonia.Utilities;
@@ -45,10 +46,27 @@ namespace Avalonia.Controls.Primitives
                 ?.AdornerLayer;
         }
 
-        protected override Size ArrangeOverride(Size finalSize)
+        protected override Size MeasureOverride(Size availableSize)
         {
-            var parent = Parent;
+            foreach (var child in Children)
+            {
+                var info = child.GetValue(s_adornedElementInfoProperty);
+
+                if (info != null && info.Bounds.HasValue)
+                {
+                    child.Measure(info.Bounds.Value.Bounds.Size);
+                }
+                else
+                {
+                    child.Measure(availableSize);
+                }
+            }
 
+            return default;
+        }
+
+        protected override Size ArrangeOverride(Size finalSize)
+        {
             foreach (var child in Children)
             {
                 var info = child.GetValue(s_adornedElementInfoProperty);
diff --git a/src/Avalonia.Controls/Repeater/ViewportManager.cs b/src/Avalonia.Controls/Repeater/ViewportManager.cs
index 6e24408aa9..da3c2b15e6 100644
--- a/src/Avalonia.Controls/Repeater/ViewportManager.cs
+++ b/src/Avalonia.Controls/Repeater/ViewportManager.cs
@@ -27,7 +27,6 @@ namespace Avalonia.Controls
         private IScrollAnchorProvider _scroller;
         private IControl _makeAnchorElement;
         private bool _isAnchorOutsideRealizedRange;
-        private Task _cacheBuildAction;
         private Rect _visibleWindow;
         private Rect _layoutExtent;
         // This is the expected shift by the layout.
diff --git a/src/Avalonia.Controls/Repeater/VirtualizationInfo.cs b/src/Avalonia.Controls/Repeater/VirtualizationInfo.cs
index f8cfde609e..7e6b24f1b5 100644
--- a/src/Avalonia.Controls/Repeater/VirtualizationInfo.cs
+++ b/src/Avalonia.Controls/Repeater/VirtualizationInfo.cs
@@ -27,7 +27,6 @@ namespace Avalonia.Controls
     internal class VirtualizationInfo
     {
         private int _pinCounter;
-        private object _data;
 
         public Rect ArrangeBounds { get; set; }
         public bool AutoRecycleCandidate { get; set; }
diff --git a/src/Avalonia.Controls/RowDefinitions.cs b/src/Avalonia.Controls/RowDefinitions.cs
index 02ab12b5af..a5ed6ae09d 100644
--- a/src/Avalonia.Controls/RowDefinitions.cs
+++ b/src/Avalonia.Controls/RowDefinitions.cs
@@ -1,5 +1,4 @@
 using System.Linq;
-using Avalonia.Collections;
 
 namespace Avalonia.Controls
 {
@@ -25,6 +24,11 @@ namespace Avalonia.Controls
             AddRange(GridLength.ParseLengths(s).Select(x => new RowDefinition(x)));
         }
 
+        public override string ToString()
+        {
+            return string.Join(",", this.Select(x => x.Height));
+        }
+
         /// <summary>
         /// Parses a string representation of row definitions collection.
         /// </summary>
@@ -32,4 +36,4 @@ namespace Avalonia.Controls
         /// <returns>The <see cref="RowDefinitions"/>.</returns>
         public static RowDefinitions Parse(string s) => new RowDefinitions(s);
     }
-}
\ No newline at end of file
+}
diff --git a/src/Avalonia.Controls/SplitView.cs b/src/Avalonia.Controls/SplitView.cs
index 4500d52484..0e35c610b2 100644
--- a/src/Avalonia.Controls/SplitView.cs
+++ b/src/Avalonia.Controls/SplitView.cs
@@ -133,7 +133,7 @@ namespace Avalonia.Controls
             AvaloniaProperty.Register<SplitView, object?>(nameof(Pane));
 
         /// <summary>
-        /// Defines the <see cref="HeaderTemplate"/> property.
+        /// Defines the <see cref="PaneTemplate"/> property.
         /// </summary>
         public static readonly StyledProperty<IDataTemplate?> PaneTemplateProperty =
             AvaloniaProperty.Register<HeaderedContentControl, IDataTemplate?>(nameof(PaneTemplate));
diff --git a/src/Avalonia.Controls/TextBox.cs b/src/Avalonia.Controls/TextBox.cs
index 1bee15bccd..c1516613b3 100644
--- a/src/Avalonia.Controls/TextBox.cs
+++ b/src/Avalonia.Controls/TextBox.cs
@@ -1290,7 +1290,7 @@ namespace Avalonia.Controls
 
         private void UpdatePseudoclasses()
         {
-            PseudoClasses.Set(":empty", string.IsNullOrWhiteSpace(Text));
+            PseudoClasses.Set(":empty", string.IsNullOrEmpty(Text));
         }
 
         private bool IsPasswordBox => PasswordChar != default(char);
diff --git a/src/Avalonia.Layout/ElementManager.cs b/src/Avalonia.Layout/ElementManager.cs
index cb13deb15f..3f106708e6 100644
--- a/src/Avalonia.Layout/ElementManager.cs
+++ b/src/Avalonia.Layout/ElementManager.cs
@@ -325,7 +325,10 @@ namespace Avalonia.Layout
                         break;
 
                     case NotifyCollectionChangedAction.Move:
-                        throw new NotImplementedException();
+                        int size = args.OldItems != null ? args.OldItems.Count : 1;
+                        OnItemsRemoved(args.OldStartingIndex, size);
+                        OnItemsAdded(args.NewStartingIndex, size);
+                        break;
                 }
             }
         }
diff --git a/src/Avalonia.ReactiveUI/TransitioningContentControl.cs b/src/Avalonia.ReactiveUI/TransitioningContentControl.cs
index 9685ecbe91..c4dd79f468 100644
--- a/src/Avalonia.ReactiveUI/TransitioningContentControl.cs
+++ b/src/Avalonia.ReactiveUI/TransitioningContentControl.cs
@@ -1,4 +1,6 @@
 using System;
+using System.Threading;
+
 using Avalonia.Animation;
 using Avalonia.Controls;
 using Avalonia.Styling;
@@ -22,7 +24,9 @@ namespace Avalonia.ReactiveUI
         /// </summary>
         public static readonly StyledProperty<object?> DefaultContentProperty =
             AvaloniaProperty.Register<TransitioningContentControl, object?>(nameof(DefaultContent));
-        
+
+        private CancellationTokenSource? _lastTransitionCts;
+
         /// <summary>
         /// Gets or sets the animation played when content appears and disappears.
         /// </summary>
@@ -62,11 +66,14 @@ namespace Avalonia.ReactiveUI
         /// <param name="content">New content to set.</param>
         private async void UpdateContentWithTransition(object? content)
         {
+            _lastTransitionCts?.Cancel();
+            _lastTransitionCts = new CancellationTokenSource();
+
             if (PageTransition != null)
-                await PageTransition.Start(this, null, true);
+                await PageTransition.Start(this, null, true, _lastTransitionCts.Token);
             base.Content = content;
             if (PageTransition != null)
-                await PageTransition.Start(null, this, true);
+                await PageTransition.Start(null, this, true, _lastTransitionCts.Token);
         }
     }
 }
diff --git a/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml b/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml
index 2eee656dc6..60420f2f44 100644
--- a/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml
@@ -112,9 +112,7 @@
                 <Panel Height="12"
                        Width="12" />
                 <Path x:Name="DropDownGlyph"
-                      Stretch="Uniform"
-                      VerticalAlignment="Center"
-                      Data="M1939 486L2029 576L1024 1581L19 576L109 486L1024 1401L1939 486Z" />
+                      VerticalAlignment="Center" />
               </Panel>
             </Viewbox>
             <Popup Name="PART_Popup"
@@ -160,6 +158,8 @@
 
   <Style Selector="ComboBox /template/ Path#DropDownGlyph">
     <Setter Property="Fill" Value="{DynamicResource ComboBoxDropDownGlyphForeground}" />
+    <Setter Property="Data" Value="M1939 486L2029 576L1024 1581L19 576L109 486L1024 1401L1939 486Z" />
+    <Setter Property="Stretch" Value="Uniform" />
   </Style>
 
   <!--  PointerOver State  -->
diff --git a/src/Avalonia.Visuals/Animation/CompositePageTransition.cs b/src/Avalonia.Visuals/Animation/CompositePageTransition.cs
index 9489914c97..2deebd7792 100644
--- a/src/Avalonia.Visuals/Animation/CompositePageTransition.cs
+++ b/src/Avalonia.Visuals/Animation/CompositePageTransition.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using Avalonia.Metadata;
 
@@ -35,25 +36,11 @@ namespace Avalonia.Animation
         [Content]
         public List<IPageTransition> PageTransitions { get; set; } = new List<IPageTransition>();
 
-        /// <summary>
-        /// Starts the animation.
-        /// </summary>
-        /// <param name="from">
-        /// The control that is being transitioned away from. May be null.
-        /// </param>
-        /// <param name="to">
-        /// The control that is being transitioned to. May be null.
-        /// </param>
-        /// <param name="forward">
-        /// Defines the direction of the transition.
-        /// </param>
-        /// <returns>
-        /// A <see cref="Task"/> that tracks the progress of the animation.
-        /// </returns>
-        public Task Start(Visual from, Visual to, bool forward)
+        /// <inheritdoc />
+        public Task Start(Visual from, Visual to, bool forward, CancellationToken cancellationToken)
         {
             var transitionTasks = PageTransitions
-                .Select(transition => transition.Start(from, to, forward))
+                .Select(transition => transition.Start(from, to, forward, cancellationToken))
                 .ToList();
             return Task.WhenAll(transitionTasks);
         }
diff --git a/src/Avalonia.Visuals/Animation/CrossFade.cs b/src/Avalonia.Visuals/Animation/CrossFade.cs
index 0615b854da..5eaa920b32 100644
--- a/src/Avalonia.Visuals/Animation/CrossFade.cs
+++ b/src/Avalonia.Visuals/Animation/CrossFade.cs
@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Reactive.Disposables;
+using System.Threading;
 using System.Threading.Tasks;
 using Avalonia.Animation.Easings;
 using Avalonia.Styling;
@@ -97,49 +99,39 @@ namespace Avalonia.Animation
             set => _fadeOutAnimation.Easing = value;
         }
 
-        /// <summary>
-        /// Starts the animation.
-        /// </summary>
-        /// <param name="from">
-        /// The control that is being transitioned away from. May be null.
-        /// </param>
-        /// <param name="to">
-        /// The control that is being transitioned to. May be null.
-        /// </param>
-        /// <returns>
-        /// A <see cref="Task"/> that tracks the progress of the animation.
-        /// </returns>
-        public async Task Start(Visual from, Visual to)
+        /// <inheritdoc cref="Start(Visual, Visual, CancellationToken)" />
+        public async Task Start(Visual from, Visual to, CancellationToken cancellationToken)
         {
-            var tasks = new List<Task>();
-
-            if (to != null)
-            {
-                to.Opacity = 0;
-            }
-
-            if (from != null)
+            if (cancellationToken.IsCancellationRequested)
             {
-                tasks.Add(_fadeOutAnimation.RunAsync(from));
+                return;
             }
 
-            if (to != null)
+            var tasks = new List<Task>();
+            using (var disposables = new CompositeDisposable())
             {
-                to.IsVisible = true;
-                tasks.Add(_fadeInAnimation.RunAsync(to));
+                if (to != null)
+                {
+                    disposables.Add(to.SetValue(Visual.OpacityProperty, 0, Data.BindingPriority.Animation));
+                }
 
-            }
+                if (from != null)
+                {
+                    tasks.Add(_fadeOutAnimation.RunAsync(from, null, cancellationToken));
+                }
 
-            await Task.WhenAll(tasks);
+                if (to != null)
+                {
+                    to.IsVisible = true;
+                    tasks.Add(_fadeInAnimation.RunAsync(to, null, cancellationToken));
+                }
 
-            if (from != null)
-            {
-                from.IsVisible = false;
-            }
+                await Task.WhenAll(tasks);
 
-            if (to != null)
-            {
-                to.Opacity = 1;
+                if (from != null && !cancellationToken.IsCancellationRequested)
+                {
+                    from.IsVisible = false;
+                }
             }
         }
 
@@ -155,12 +147,13 @@ namespace Avalonia.Animation
         /// <param name="forward">
         /// Unused for cross-fades.
         /// </param>
+        /// <param name="cancellationToken">allowed cancel transition</param>
         /// <returns>
         /// A <see cref="Task"/> that tracks the progress of the animation.
         /// </returns>
-        Task IPageTransition.Start(Visual from, Visual to, bool forward)
+        Task IPageTransition.Start(Visual from, Visual to, bool forward, CancellationToken cancellationToken)
         {
-            return Start(from, to);
+            return Start(from, to, cancellationToken);
         }
     }
 }
diff --git a/src/Avalonia.Visuals/Animation/IPageTransition.cs b/src/Avalonia.Visuals/Animation/IPageTransition.cs
index 659bc12424..2d19ddbb5b 100644
--- a/src/Avalonia.Visuals/Animation/IPageTransition.cs
+++ b/src/Avalonia.Visuals/Animation/IPageTransition.cs
@@ -1,3 +1,4 @@
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Avalonia.Animation
@@ -19,9 +20,12 @@ namespace Avalonia.Animation
         /// <param name="forward">
         /// If the animation is bidirectional, controls the direction of the animation.
         /// </param>
+        /// <param name="cancellationToken">
+        /// Animation cancellation.
+        /// </param>
         /// <returns>
         /// A <see cref="Task"/> that tracks the progress of the animation.
         /// </returns>
-        Task Start(Visual from, Visual to, bool forward);
+        Task Start(Visual from, Visual to, bool forward, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Avalonia.Visuals/Animation/PageSlide.cs b/src/Avalonia.Visuals/Animation/PageSlide.cs
index dd5d598e12..7d033ccf61 100644
--- a/src/Avalonia.Visuals/Animation/PageSlide.cs
+++ b/src/Avalonia.Visuals/Animation/PageSlide.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
 using Avalonia.Animation.Easings;
 using Avalonia.Media;
@@ -60,23 +61,14 @@ namespace Avalonia.Animation
         /// </summary>
         public Easing SlideOutEasing { get; set; } = new LinearEasing();
 
-        /// <summary>
-        /// Starts the animation.
-        /// </summary>
-        /// <param name="from">
-        /// The control that is being transitioned away from. May be null.
-        /// </param>
-        /// <param name="to">
-        /// The control that is being transitioned to. May be null.
-        /// </param>
-        /// <param name="forward">
-        /// If true, the new page is slid in from the right, or if false from the left.
-        /// </param>
-        /// <returns>
-        /// A <see cref="Task"/> that tracks the progress of the animation.
-        /// </returns>
-        public async Task Start(Visual from, Visual to, bool forward)
+        /// <inheritdoc />
+        public async Task Start(Visual from, Visual to, bool forward, CancellationToken cancellationToken)
         {
+            if (cancellationToken.IsCancellationRequested)
+            {
+                return;
+            }
+
             var tasks = new List<Task>();
             var parent = GetVisualParent(from, to);
             var distance = Orientation == SlideAxis.Horizontal ? parent.Bounds.Width : parent.Bounds.Height;
@@ -109,7 +101,7 @@ namespace Avalonia.Animation
                     },
                     Duration = Duration
                 };
-                tasks.Add(animation.RunAsync(from));
+                tasks.Add(animation.RunAsync(from, null, cancellationToken));
             }
 
             if (to != null)
@@ -140,12 +132,12 @@ namespace Avalonia.Animation
                     },
                     Duration = Duration
                 };
-                tasks.Add(animation.RunAsync(to));
+                tasks.Add(animation.RunAsync(to, null, cancellationToken));
             }
 
             await Task.WhenAll(tasks);
 
-            if (from != null)
+            if (from != null && !cancellationToken.IsCancellationRequested)
             {
                 from.IsVisible = false;
             }
diff --git a/src/Avalonia.Visuals/ApiCompatBaseline.txt b/src/Avalonia.Visuals/ApiCompatBaseline.txt
index f9fd125615..c917902dc3 100644
--- a/src/Avalonia.Visuals/ApiCompatBaseline.txt
+++ b/src/Avalonia.Visuals/ApiCompatBaseline.txt
@@ -1,4 +1,10 @@
 Compat issues with assembly Avalonia.Visuals:
+MembersMustExist : Member 'public System.Threading.Tasks.Task Avalonia.Animation.CompositePageTransition.Start(Avalonia.Visual, Avalonia.Visual, System.Boolean)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public System.Threading.Tasks.Task Avalonia.Animation.CrossFade.Start(Avalonia.Visual, Avalonia.Visual)' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Threading.Tasks.Task Avalonia.Animation.IPageTransition.Start(Avalonia.Visual, Avalonia.Visual, System.Boolean)' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public System.Threading.Tasks.Task Avalonia.Animation.IPageTransition.Start(Avalonia.Visual, Avalonia.Visual, System.Boolean)' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Threading.Tasks.Task Avalonia.Animation.IPageTransition.Start(Avalonia.Visual, Avalonia.Visual, System.Boolean, System.Threading.CancellationToken)' is present in the implementation but not in the contract.
+MembersMustExist : Member 'public System.Threading.Tasks.Task Avalonia.Animation.PageSlide.Start(Avalonia.Visual, Avalonia.Visual, System.Boolean)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public void Avalonia.Media.TextFormatting.DrawableTextRun.Draw(Avalonia.Media.DrawingContext)' does not exist in the implementation but it does exist in the contract.
 CannotAddAbstractMembers : Member 'public void Avalonia.Media.TextFormatting.DrawableTextRun.Draw(Avalonia.Media.DrawingContext, Avalonia.Point)' is abstract in the implementation but is missing in the contract.
 CannotSealType : Type 'Avalonia.Media.TextFormatting.GenericTextParagraphProperties' is actually (has the sealed modifier) sealed in the implementation but not sealed in the contract.
@@ -63,9 +69,8 @@ InterfacesShouldHaveSameMembers : Interface member 'public System.Boolean Avalon
 InterfacesShouldHaveSameMembers : Interface member 'public Avalonia.Platform.IGlyphRunImpl Avalonia.Platform.IPlatformRenderInterface.CreateGlyphRun(Avalonia.Media.GlyphRun)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public Avalonia.Platform.IGlyphRunImpl Avalonia.Platform.IPlatformRenderInterface.CreateGlyphRun(Avalonia.Media.GlyphRun, System.Double)' is present in the contract but not in the implementation.
 MembersMustExist : Member 'public Avalonia.Platform.IGlyphRunImpl Avalonia.Platform.IPlatformRenderInterface.CreateGlyphRun(Avalonia.Media.GlyphRun, System.Double)' does not exist in the implementation but it does exist in the contract.
-Total Issues: 64
 InterfacesShouldHaveSameMembers : Interface member 'public Avalonia.Platform.IWriteableBitmapImpl Avalonia.Platform.IPlatformRenderInterface.LoadWriteableBitmap(System.IO.Stream)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public Avalonia.Platform.IWriteableBitmapImpl Avalonia.Platform.IPlatformRenderInterface.LoadWriteableBitmap(System.String)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public Avalonia.Platform.IWriteableBitmapImpl Avalonia.Platform.IPlatformRenderInterface.LoadWriteableBitmapToHeight(System.IO.Stream, System.Int32, Avalonia.Visuals.Media.Imaging.BitmapInterpolationMode)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public Avalonia.Platform.IWriteableBitmapImpl Avalonia.Platform.IPlatformRenderInterface.LoadWriteableBitmapToWidth(System.IO.Stream, System.Int32, Avalonia.Visuals.Media.Imaging.BitmapInterpolationMode)' is present in the implementation but not in the contract.
-Total Issues: 11
+Total Issues: 74
diff --git a/src/Avalonia.Visuals/Media/BoxShadow.cs b/src/Avalonia.Visuals/Media/BoxShadow.cs
index 69395fd3b8..50f75365b0 100644
--- a/src/Avalonia.Visuals/Media/BoxShadow.cs
+++ b/src/Avalonia.Visuals/Media/BoxShadow.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Globalization;
+using System.Text;
 using Avalonia.Animation.Animators;
 using Avalonia.Utilities;
 
@@ -75,6 +76,46 @@ namespace Avalonia.Media
                 return rv;
             }
         }
+
+        public override string ToString()
+        {
+            var sb = new StringBuilder();
+
+            if (IsEmpty)
+            {
+                return "none";
+            }
+
+            if (IsInset)
+            {
+                sb.Append("inset");
+            }
+
+            if (OffsetX != 0.0)
+            {
+                sb.AppendFormat(" {0}", OffsetX.ToString());
+            }
+
+            if (OffsetY != 0.0)
+            {
+                sb.AppendFormat(" {0}", OffsetY.ToString());
+            }
+            
+            if (Blur != 0.0)
+            {
+                sb.AppendFormat(" {0}", Blur.ToString());
+            }
+
+            if (Spread != 0.0)
+            {
+                sb.AppendFormat(" {0}", Spread.ToString());
+            }
+
+            sb.AppendFormat(" {0}", Color.ToString());
+
+            return sb.ToString();
+        }
+
         public static unsafe BoxShadow Parse(string s)
         {
             if(s == null)
diff --git a/src/Avalonia.Visuals/Media/BoxShadows.cs b/src/Avalonia.Visuals/Media/BoxShadows.cs
index 9e4d6aacb0..810ac70b99 100644
--- a/src/Avalonia.Visuals/Media/BoxShadows.cs
+++ b/src/Avalonia.Visuals/Media/BoxShadows.cs
@@ -1,6 +1,6 @@
 using System;
-using System.Collections.Generic;
 using System.ComponentModel;
+using System.Text;
 using Avalonia.Animation.Animators;
 
 namespace Avalonia.Media
@@ -43,6 +43,24 @@ namespace Avalonia.Media
             }
         }
 
+        public override string ToString()
+        {
+            var sb = new StringBuilder();
+
+            if (Count == 0)
+            {
+                return "none";
+            }
+
+            foreach (var boxShadow in this)
+            {
+                sb.AppendFormat("{0} ", boxShadow.ToString());
+            }
+
+            return sb.ToString();
+
+        }
+
         [EditorBrowsable(EditorBrowsableState.Never)]
         public struct BoxShadowsEnumerator
         {
diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/BitmapBlendModeNode.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/BitmapBlendModeNode.cs
index 0a5c1f8db6..45b62b843b 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/BitmapBlendModeNode.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/BitmapBlendModeNode.cs
@@ -19,7 +19,7 @@ namespace Avalonia.Rendering.SceneGraph
         }
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="BitmapBlendNode"/> class that represents an
+        /// Initializes a new instance of the <see cref="BitmapBlendModeNode"/> class that represents an
         /// <see cref="BitmapBlendingMode"/> pop.
         /// </summary>
         public BitmapBlendModeNode()
@@ -40,7 +40,7 @@ namespace Avalonia.Rendering.SceneGraph
         /// <summary>
         /// Determines if this draw operation equals another.
         /// </summary>
-        /// <param name="opacity">The opacity of the other draw operation.</param>
+        /// <param name="blendingMode">the <see cref="BitmapBlendModeNode"/> how to compare</param>
         /// <returns>True if the draw operations are the same, otherwise false.</returns>
         /// <remarks>
         /// The properties of the other draw operation are passed in as arguments to prevent
diff --git a/src/Avalonia.X11/TransparencyHelper.cs b/src/Avalonia.X11/TransparencyHelper.cs
index 0578680136..2140b61b6f 100644
--- a/src/Avalonia.X11/TransparencyHelper.cs
+++ b/src/Avalonia.X11/TransparencyHelper.cs
@@ -10,7 +10,6 @@ namespace Avalonia.X11
         private readonly X11Globals _globals;
         private WindowTransparencyLevel _currentLevel;
         private WindowTransparencyLevel _requestedLevel;
-        private bool _isCompositing;
         private bool _blurAtomsAreSet;
         
         public Action<WindowTransparencyLevel> TransparencyLevelChanged { get; set; }
diff --git a/src/Avalonia.X11/X11Window.cs b/src/Avalonia.X11/X11Window.cs
index 3425da5deb..bcb655245a 100644
--- a/src/Avalonia.X11/X11Window.cs
+++ b/src/Avalonia.X11/X11Window.cs
@@ -30,7 +30,6 @@ namespace Avalonia.X11
         ITopLevelImplWithTextInputMethod
     {
         private readonly AvaloniaX11Platform _platform;
-        private readonly IWindowImpl _popupParent;
         private readonly bool _popup;
         private readonly X11Info _x11;
         private XConfigureEvent? _configure;
diff --git a/src/Linux/Avalonia.LinuxFramebuffer/FramebufferToplevelImpl.cs b/src/Linux/Avalonia.LinuxFramebuffer/FramebufferToplevelImpl.cs
index 73b1b87ce9..5a1da9058a 100644
--- a/src/Linux/Avalonia.LinuxFramebuffer/FramebufferToplevelImpl.cs
+++ b/src/Linux/Avalonia.LinuxFramebuffer/FramebufferToplevelImpl.cs
@@ -15,7 +15,6 @@ namespace Avalonia.LinuxFramebuffer
         private readonly IOutputBackend _outputBackend;
         private readonly IInputBackend _inputBackend;
 
-        private bool _renderQueued;
         public IInputRoot InputRoot { get; private set; }
 
         public FramebufferToplevelImpl(IOutputBackend outputBackend, IInputBackend inputBackend)
diff --git a/src/Linux/Avalonia.LinuxFramebuffer/Input/EvDev/EvDevTouchScreen.cs b/src/Linux/Avalonia.LinuxFramebuffer/Input/EvDev/EvDevTouchScreen.cs
index b69b151c3b..c35a3d1174 100644
--- a/src/Linux/Avalonia.LinuxFramebuffer/Input/EvDev/EvDevTouchScreen.cs
+++ b/src/Linux/Avalonia.LinuxFramebuffer/Input/EvDev/EvDevTouchScreen.cs
@@ -7,7 +7,6 @@ namespace Avalonia.LinuxFramebuffer.Input.EvDev
     internal class EvDevSingleTouchScreen : EvDevDeviceHandler
     {
         private readonly IScreenInfoProvider _screenInfo;
-        private readonly int _width, _height;
         private readonly Matrix _calibration;
         private input_absinfo _axisX;
         private input_absinfo _axisY;
diff --git a/src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebufferPlatform.cs b/src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebufferPlatform.cs
index a6b70069c1..89f81a7649 100644
--- a/src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebufferPlatform.cs
+++ b/src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebufferPlatform.cs
@@ -132,7 +132,10 @@ public static class LinuxFramebufferPlatformExtensions
 {
     public static int StartLinuxFbDev<T>(this T builder, string[] args, string fbdev = null, double scaling = 1)
         where T : AppBuilderBase<T>, new() =>
-        StartLinuxDirect(builder, args, new FbdevOutput(fbdev) {Scaling = scaling});
+        StartLinuxDirect(builder, args, new FbdevOutput(fileName: fbdev, format: null) { Scaling = scaling });
+    public static int StartLinuxFbDev<T>(this T builder, string[] args, string fbdev, PixelFormat? format, double scaling)
+        where T : AppBuilderBase<T>, new() =>
+        StartLinuxDirect(builder, args, new FbdevOutput(fileName: fbdev, format: format) { Scaling = scaling });
 
     public static int StartLinuxDrm<T>(this T builder, string[] args, string card = null, double scaling = 1)
         where T : AppBuilderBase<T>, new() => StartLinuxDirect(builder, args, new DrmOutput(card) {Scaling = scaling});
diff --git a/src/Linux/Avalonia.LinuxFramebuffer/LockedFramebuffer.cs b/src/Linux/Avalonia.LinuxFramebuffer/LockedFramebuffer.cs
index ed59166eb8..87c7b64c26 100644
--- a/src/Linux/Avalonia.LinuxFramebuffer/LockedFramebuffer.cs
+++ b/src/Linux/Avalonia.LinuxFramebuffer/LockedFramebuffer.cs
@@ -41,6 +41,6 @@ namespace Avalonia.LinuxFramebuffer
         public PixelSize Size => new PixelSize((int)_varInfo.xres, (int) _varInfo.yres);
         public int RowBytes => (int) _fixedInfo.line_length;
         public Vector Dpi { get; }
-        public PixelFormat Format => _varInfo.blue.offset == 16 ? PixelFormat.Rgba8888 : PixelFormat.Bgra8888;
+        public PixelFormat Format => _varInfo.bits_per_pixel == 16 ? PixelFormat.Rgb565 : _varInfo.blue.offset == 16 ? PixelFormat.Rgba8888 : PixelFormat.Bgra8888;
     }
 }
diff --git a/src/Linux/Avalonia.LinuxFramebuffer/Output/DrmOutput.cs b/src/Linux/Avalonia.LinuxFramebuffer/Output/DrmOutput.cs
index dc44d2d55f..ee4125101c 100644
--- a/src/Linux/Avalonia.LinuxFramebuffer/Output/DrmOutput.cs
+++ b/src/Linux/Avalonia.LinuxFramebuffer/Output/DrmOutput.cs
@@ -16,7 +16,6 @@ namespace Avalonia.LinuxFramebuffer.Output
     public unsafe class DrmOutput : IGlOutputBackend, IGlPlatformSurface
     {
         private DrmCard _card;
-        private readonly EglGlPlatformSurface _eglPlatformSurface;
         public PixelSize PixelSize => _mode.Resolution;
         public double Scaling { get; set; }
         public IGlContext PrimaryContext => _deferredContext;
diff --git a/src/Linux/Avalonia.LinuxFramebuffer/Output/FbdevOutput.cs b/src/Linux/Avalonia.LinuxFramebuffer/Output/FbdevOutput.cs
index b83fe6cbe8..61f00b2795 100644
--- a/src/Linux/Avalonia.LinuxFramebuffer/Output/FbdevOutput.cs
+++ b/src/Linux/Avalonia.LinuxFramebuffer/Output/FbdevOutput.cs
@@ -16,16 +16,33 @@ namespace Avalonia.LinuxFramebuffer
         private IntPtr _mappedAddress;
         public double Scaling { get; set; }
 
-        public FbdevOutput(string fileName = null)
+        /// <summary>
+        /// Create a Linux frame buffer device output
+        /// </summary>
+        /// <param name="fileName">The frame buffer device name.
+        /// Defaults to the value in environment variable FRAMEBUFFER or /dev/fb0 when FRAMEBUFFER is not set</param>
+        public FbdevOutput(string fileName = null) : this(fileName, null)
         {
-            fileName = fileName ?? Environment.GetEnvironmentVariable("FRAMEBUFFER") ?? "/dev/fb0";
+        }
+
+        /// <summary>
+        /// Create a Linux frame buffer device output
+        /// </summary>
+        /// <param name="fileName">The frame buffer device name.
+        /// Defaults to the value in environment variable FRAMEBUFFER or /dev/fb0 when FRAMEBUFFER is not set</param>
+        /// <param name="format">The required pixel format for the frame buffer.
+        /// A null value will leave the frame buffer in the current pixel format.
+        /// Otherwise sets the frame buffer to the required format</param>
+        public FbdevOutput(string fileName, PixelFormat? format)
+        {
+            fileName ??= Environment.GetEnvironmentVariable("FRAMEBUFFER") ?? "/dev/fb0";
             _fd = NativeUnsafeMethods.open(fileName, 2, 0);
             if (_fd <= 0)
                 throw new Exception("Error: " + Marshal.GetLastWin32Error());
 
             try
             {
-                Init();
+                Init(format);
             }
             catch
             {
@@ -34,25 +51,28 @@ namespace Avalonia.LinuxFramebuffer
             }
         }
 
-        void Init()
+        void Init(PixelFormat? format)
         {
             fixed (void* pnfo = &_varInfo)
             {
                 if (-1 == NativeUnsafeMethods.ioctl(_fd, FbIoCtl.FBIOGET_VSCREENINFO, pnfo))
                     throw new Exception("FBIOGET_VSCREENINFO error: " + Marshal.GetLastWin32Error());
 
-                SetBpp();
+                if (format.HasValue)
+                {
+                    SetBpp(format.Value);
 
-                if (-1 == NativeUnsafeMethods.ioctl(_fd, FbIoCtl.FBIOPUT_VSCREENINFO, pnfo))
-                    _varInfo.transp = new fb_bitfield();
+                    if (-1 == NativeUnsafeMethods.ioctl(_fd, FbIoCtl.FBIOPUT_VSCREENINFO, pnfo))
+                        _varInfo.transp = new fb_bitfield();
 
-                NativeUnsafeMethods.ioctl(_fd, FbIoCtl.FBIOPUT_VSCREENINFO, pnfo);
+                    NativeUnsafeMethods.ioctl(_fd, FbIoCtl.FBIOPUT_VSCREENINFO, pnfo);
 
-                if (-1 == NativeUnsafeMethods.ioctl(_fd, FbIoCtl.FBIOGET_VSCREENINFO, pnfo))
-                    throw new Exception("FBIOGET_VSCREENINFO error: " + Marshal.GetLastWin32Error());
+                    if (-1 == NativeUnsafeMethods.ioctl(_fd, FbIoCtl.FBIOGET_VSCREENINFO, pnfo))
+                        throw new Exception("FBIOGET_VSCREENINFO error: " + Marshal.GetLastWin32Error());
 
-                if (_varInfo.bits_per_pixel != 32)
-                    throw new Exception("Unable to set 32-bit display mode");
+                    if (_varInfo.bits_per_pixel != 32)
+                        throw new Exception("Unable to set 32-bit display mode");
+                }
             }
             fixed(void*pnfo = &_fixedInfo)
                 if (-1 == NativeUnsafeMethods.ioctl(_fd, FbIoCtl.FBIOGET_FSCREENINFO, pnfo))
@@ -70,17 +90,43 @@ namespace Avalonia.LinuxFramebuffer
             }
         }
 
-        void SetBpp()
+        void SetBpp(PixelFormat format)
         {
-            _varInfo.bits_per_pixel = 32;
-            _varInfo.grayscale = 0;
-            _varInfo.red = _varInfo.blue = _varInfo.green = _varInfo.transp = new fb_bitfield
+            switch (format)
             {
-                length = 8
-            };
-            _varInfo.green.offset = 8;
-            _varInfo.blue.offset = 16;
-            _varInfo.transp.offset = 24;
+            case PixelFormat.Rgba8888:
+                _varInfo.bits_per_pixel = 32;
+                _varInfo.grayscale = 0;
+                _varInfo.red = _varInfo.blue = _varInfo.green = _varInfo.transp = new fb_bitfield
+                {
+                    length = 8
+                };
+                _varInfo.green.offset = 8;
+                _varInfo.blue.offset = 16;
+                _varInfo.transp.offset = 24;
+                 break;
+            case PixelFormat.Bgra8888:
+                _varInfo.bits_per_pixel = 32;
+                _varInfo.grayscale = 0;
+                _varInfo.red = _varInfo.blue = _varInfo.green = _varInfo.transp = new fb_bitfield
+                {
+                    length = 8
+                };
+                _varInfo.green.offset = 8;
+                _varInfo.red.offset = 16;
+                _varInfo.transp.offset = 24;
+                 break;
+            case PixelFormat.Rgb565:
+                _varInfo.bits_per_pixel = 16;
+                _varInfo.grayscale = 0;
+                _varInfo.red = _varInfo.blue = _varInfo.green = _varInfo.transp = new fb_bitfield();
+                _varInfo.red.length = 5;
+                _varInfo.green.offset = 5;
+                _varInfo.green.length = 6;
+                _varInfo.blue.offset = 11;
+                _varInfo.blue.length = 5;
+                 break;
+            }
         }
 
         public string Id { get; private set; }
diff --git a/src/Skia/Avalonia.Skia/DrawingContextImpl.cs b/src/Skia/Avalonia.Skia/DrawingContextImpl.cs
index d8bd0607d1..2352b8b076 100644
--- a/src/Skia/Avalonia.Skia/DrawingContextImpl.cs
+++ b/src/Skia/Avalonia.Skia/DrawingContextImpl.cs
@@ -591,7 +591,7 @@ namespace Avalonia.Skia
         /// Configure paint wrapper for using gradient brush.
         /// </summary>
         /// <param name="paintWrapper">Paint wrapper.</param>
-        /// <param name="targetSize">Target size.</param>
+        /// <param name="targetRect">Target bound rect.</param>
         /// <param name="gradientBrush">Gradient brush.</param>
         private void ConfigureGradientBrush(ref PaintWrapper paintWrapper, Rect targetRect, IGradientBrush gradientBrush)
         {
diff --git a/src/Skia/Avalonia.Skia/Gpu/ISkiaGpu.cs b/src/Skia/Avalonia.Skia/Gpu/ISkiaGpu.cs
index aa86df7c23..32818dfdd2 100644
--- a/src/Skia/Avalonia.Skia/Gpu/ISkiaGpu.cs
+++ b/src/Skia/Avalonia.Skia/Gpu/ISkiaGpu.cs
@@ -16,11 +16,12 @@ namespace Avalonia.Skia
         /// <param name="surfaces">Surfaces.</param>
         /// <returns>Created render target or <see langword="null"/> if it fails.</returns>
         ISkiaGpuRenderTarget TryCreateRenderTarget(IEnumerable<object> surfaces);
-        
+
         /// <summary>
         /// Creates an offscreen render target surface
         /// </summary>
         /// <param name="size">size in pixels</param>
+        /// <param name="session">current Skia render session</param>
         ISkiaSurface TryCreateSurface(PixelSize size, ISkiaGpuRenderSession session);
     }
     
diff --git a/src/Windows/Avalonia.Win32/WinRT/Composition/WinUICompositorConnection.cs b/src/Windows/Avalonia.Win32/WinRT/Composition/WinUICompositorConnection.cs
index 2aa82436f6..1c3c959acf 100644
--- a/src/Windows/Avalonia.Win32/WinRT/Composition/WinUICompositorConnection.cs
+++ b/src/Windows/Avalonia.Win32/WinRT/Composition/WinUICompositorConnection.cs
@@ -17,7 +17,6 @@ namespace Avalonia.Win32.WinRT.Composition
     class WinUICompositorConnection : IRenderTimer
     {
         private readonly EglContext _syncContext;
-        private IntPtr _queue;
         private ICompositor _compositor;
         private ICompositor2 _compositor2;
         private ICompositor5 _compositor5;
diff --git a/tests/Avalonia.Animation.UnitTests/AnimationIterationTests.cs b/tests/Avalonia.Animation.UnitTests/AnimationIterationTests.cs
index fe718ec32b..58bd7a42c3 100644
--- a/tests/Avalonia.Animation.UnitTests/AnimationIterationTests.cs
+++ b/tests/Avalonia.Animation.UnitTests/AnimationIterationTests.cs
@@ -9,6 +9,8 @@ using Avalonia.UnitTests;
 using Avalonia.Data;
 using Xunit;
 using Avalonia.Animation.Easings;
+using System.Threading;
+using System.Reactive.Linq;
 
 namespace Avalonia.Animation.UnitTests
 {
@@ -176,5 +178,271 @@ namespace Avalonia.Animation.UnitTests
             clock.Step(TimeSpan.FromSeconds(0.100d));
             Assert.Equal(border.Width, 300d);
         }
+
+        [Fact(Skip = "See #6111")]
+        public void Dispose_Subscription_Should_Stop_Animation()
+        {
+            var keyframe1 = new KeyFrame()
+            {
+                Setters =
+                {
+                    new Setter(Border.WidthProperty, 200d),
+                },
+                Cue = new Cue(1d)
+            };
+
+            var keyframe2 = new KeyFrame()
+            {
+                Setters =
+                {
+                    new Setter(Border.WidthProperty, 100d),
+                },
+                Cue = new Cue(0d)
+            };
+
+            var animation = new Animation()
+            {
+                Duration = TimeSpan.FromSeconds(10),
+                Delay = TimeSpan.FromSeconds(0),
+                DelayBetweenIterations = TimeSpan.FromSeconds(0),
+                IterationCount = new IterationCount(1),
+                Children =
+                {
+                    keyframe2,
+                    keyframe1
+                }
+            };
+
+            var border = new Border()
+            {
+                Height = 100d,
+                Width = 50d
+            };
+            var propertyChangedCount = 0;
+            var animationCompletedCount = 0;
+            border.PropertyChanged += (sender, e) =>
+            {
+                if (e.Property == Control.WidthProperty)
+                {
+                    propertyChangedCount++;
+                }
+            };
+
+            var clock = new TestClock();
+            var disposable = animation.Apply(border, clock, Observable.Return(true), () => animationCompletedCount++);
+
+            Assert.Equal(0, propertyChangedCount);
+
+            clock.Step(TimeSpan.FromSeconds(0));
+            Assert.Equal(0, animationCompletedCount);
+            Assert.Equal(1, propertyChangedCount);
+
+            disposable.Dispose();
+
+            // Clock ticks should be ignored after Dispose
+            clock.Step(TimeSpan.FromSeconds(5));
+            clock.Step(TimeSpan.FromSeconds(6));
+            clock.Step(TimeSpan.FromSeconds(7));
+
+            // On animation disposing (cancellation) on completed is not invoked (is it expected?)
+            Assert.Equal(0, animationCompletedCount);
+            // Initial property changed before cancellation + animation value removal.
+            Assert.Equal(2, propertyChangedCount);
+        }
+
+        [Fact]
+        public void Do_Not_Run_Cancelled_Animation()
+        {
+            var keyframe1 = new KeyFrame()
+            {
+                Setters =
+                {
+                    new Setter(Border.WidthProperty, 200d),
+                },
+                Cue = new Cue(1d)
+            };
+
+            var keyframe2 = new KeyFrame()
+            {
+                Setters =
+                {
+                    new Setter(Border.WidthProperty, 100d),
+                },
+                Cue = new Cue(0d)
+            };
+
+            var animation = new Animation()
+            {
+                Duration = TimeSpan.FromSeconds(10),
+                Delay = TimeSpan.FromSeconds(0),
+                DelayBetweenIterations = TimeSpan.FromSeconds(0),
+                IterationCount = new IterationCount(1),
+                Children =
+                {
+                    keyframe2,
+                    keyframe1
+                }
+            };
+
+            var border = new Border()
+            {
+                Height = 100d,
+                Width = 100d
+            };
+            var propertyChangedCount = 0;
+            border.PropertyChanged += (sender, e) =>
+            {
+                if (e.Property == Control.WidthProperty)
+                {
+                    propertyChangedCount++;
+                }
+            };
+
+            var clock = new TestClock();
+            var cancellationTokenSource = new CancellationTokenSource();
+            cancellationTokenSource.Cancel();
+            var animationRun = animation.RunAsync(border, clock, cancellationTokenSource.Token);
+
+            clock.Step(TimeSpan.FromSeconds(10));
+            Assert.Equal(0, propertyChangedCount);
+            Assert.True(animationRun.IsCompleted);
+        }
+
+        [Fact(Skip = "See #6111")]
+        public void Cancellation_Should_Stop_Animation()
+        {
+            var keyframe1 = new KeyFrame()
+            {
+                Setters =
+                {
+                    new Setter(Border.WidthProperty, 200d),
+                },
+                Cue = new Cue(1d)
+            };
+
+            var keyframe2 = new KeyFrame()
+            {
+                Setters =
+                {
+                    new Setter(Border.WidthProperty, 100d),
+                },
+                Cue = new Cue(0d)
+            };
+
+            var animation = new Animation()
+            {
+                Duration = TimeSpan.FromSeconds(10),
+                Delay = TimeSpan.FromSeconds(0),
+                DelayBetweenIterations = TimeSpan.FromSeconds(0),
+                IterationCount = new IterationCount(1),
+                Children =
+                {
+                    keyframe2,
+                    keyframe1
+                }
+            };
+
+            var border = new Border()
+            {
+                Height = 100d,
+                Width = 50d
+            };
+            var propertyChangedCount = 0;
+            border.PropertyChanged += (sender, e) =>
+            {
+                if (e.Property == Control.WidthProperty)
+                {
+                    propertyChangedCount++;
+                }
+            };
+
+            var clock = new TestClock();
+            var cancellationTokenSource = new CancellationTokenSource();
+            var animationRun = animation.RunAsync(border, clock, cancellationTokenSource.Token);
+
+            Assert.Equal(0, propertyChangedCount);
+
+            clock.Step(TimeSpan.FromSeconds(0));
+            Assert.False(animationRun.IsCompleted);
+            Assert.Equal(1, propertyChangedCount);
+
+            cancellationTokenSource.Cancel();
+            clock.Step(TimeSpan.FromSeconds(1));
+            clock.Step(TimeSpan.FromSeconds(2));
+            clock.Step(TimeSpan.FromSeconds(3));
+            //Assert.Equal(2, propertyChangedCount);
+
+            animationRun.Wait();
+
+            clock.Step(TimeSpan.FromSeconds(6));
+            Assert.True(animationRun.IsCompleted);
+            Assert.Equal(2, propertyChangedCount);
+        }
+
+        [Fact]
+        public void Cancellation_Of_Completed_Animation_Does_Not_Fail()
+        {
+            var keyframe1 = new KeyFrame()
+            {
+                Setters =
+                {
+                    new Setter(Border.WidthProperty, 200d),
+                },
+                Cue = new Cue(1d)
+            };
+
+            var keyframe2 = new KeyFrame()
+            {
+                Setters =
+                {
+                    new Setter(Border.WidthProperty, 100d),
+                },
+                Cue = new Cue(0d)
+            };
+
+            var animation = new Animation()
+            {
+                Duration = TimeSpan.FromSeconds(10),
+                Delay = TimeSpan.FromSeconds(0),
+                DelayBetweenIterations = TimeSpan.FromSeconds(0),
+                IterationCount = new IterationCount(1),
+                Children =
+                {
+                    keyframe2,
+                    keyframe1
+                }
+            };
+
+            var border = new Border()
+            {
+                Height = 100d,
+                Width = 50d
+            };
+            var propertyChangedCount = 0;
+            border.PropertyChanged += (sender, e) =>
+            {
+                if (e.Property == Control.WidthProperty)
+                {
+                    propertyChangedCount++;
+                }
+            };
+
+            var clock = new TestClock();
+            var cancellationTokenSource = new CancellationTokenSource();
+            var animationRun = animation.RunAsync(border, clock, cancellationTokenSource.Token);
+
+            Assert.Equal(0, propertyChangedCount);
+
+            clock.Step(TimeSpan.FromSeconds(0));
+            Assert.False(animationRun.IsCompleted);
+            Assert.Equal(1, propertyChangedCount);
+
+            clock.Step(TimeSpan.FromSeconds(10));
+            Assert.True(animationRun.IsCompleted);
+            Assert.Equal(2, propertyChangedCount);
+
+            cancellationTokenSource.Cancel();
+            animationRun.Wait();
+        }
     }
 }
diff --git a/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs b/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
index 8f9c7fdb0b..cb2fd11175 100644
--- a/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
@@ -201,6 +201,65 @@ namespace Avalonia.Controls.UnitTests
                 
             }
             
-        } 
+        }
+
+        [Fact]
+        public void Close_Window_On_Alt_F4_When_ComboBox_Is_Focus()
+        {
+            var inputManagerMock = new Moq.Mock<IInputManager>();
+            var services = TestServices.StyledWindow.With(inputManager: inputManagerMock.Object);
+
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var window = new Window();
+
+                window.KeyDown += (s, e) =>
+                 {
+                     if (e.Handled == false 
+                     && e.KeyModifiers.HasAllFlags(KeyModifiers.Alt) == true 
+                     && e.Key == Key.F4 )
+                     {
+                         e.Handled = true;
+                         window.Close();
+                     }
+                 };
+
+                var count = 0;
+
+                var target = new ComboBox
+                {
+                    Items = new[] { new Canvas() },
+                    SelectedIndex = 0,
+                    Template = GetTemplate(),
+                };
+
+                window.Content = target;
+
+
+                window.Closing +=
+                    (sender, e) =>
+                    {
+                        count++;
+                    };
+
+                window.Show();
+
+                target.Focus();
+
+                _helper.Down(target);
+                _helper.Up(target);
+                Assert.True(target.IsDropDownOpen);
+
+                target.RaiseEvent(new KeyEventArgs
+                {
+                    RoutedEvent = InputElement.KeyDownEvent,
+                    KeyModifiers = KeyModifiers.Alt,
+                    Key = Key.F4
+                });
+
+
+                Assert.Equal(1, count);
+            }
+        }
     }
 }
diff --git a/tests/Avalonia.Controls.UnitTests/TreeViewTests.cs b/tests/Avalonia.Controls.UnitTests/TreeViewTests.cs
index cea77bb7c9..72ba3ab273 100644
--- a/tests/Avalonia.Controls.UnitTests/TreeViewTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/TreeViewTests.cs
@@ -1066,7 +1066,7 @@ namespace Avalonia.Controls.UnitTests
         [Fact]
         public void Auto_Expanding_In_Style_Should_Not_Break_Range_Selection()
         {
-            /// Issue #2980.
+            // Issue #2980.
             using (Application())
             {
                 var target = new DerivedTreeView