Merge branch 'master' into alloc-boxing

CODE_OF_CONDUCT.md

@@ -0,0 +1,76 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, sex characteristics, gender identity and expression,
+level of experience, education, socio-economic status, nationality, personal
+appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+ advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+ address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+ professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at steven@avaloniaui.net. All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
+
+[homepage]: https://www.contributor-covenant.org
+
+For answers to common questions about this code of conduct, see
+https://www.contributor-covenant.org/faq

src/Avalonia.Animation/Properties/AssemblyInfo.cs

@@ -10,3 +10,4 @@ using System.Runtime.CompilerServices;
 [assembly: XmlnsDefinition("https://github.com/avaloniaui", "Avalonia.Animation.Animators")]
 
 [assembly: InternalsVisibleTo("Avalonia.LeakTests")]
+[assembly: InternalsVisibleTo("Avalonia.Animation.UnitTests")]

src/Avalonia.Animation/TransitionInstance.cs

@@ -28,7 +28,7 @@ namespace Avalonia.Animation
 
         private void TimerTick(TimeSpan t)
         {
-            var interpVal = (double)t.Ticks / _duration.Ticks;
+            var interpVal = _duration.Ticks == 0 ? 1d : (double)t.Ticks / _duration.Ticks;
 
             // Clamp interpolation value.
             if (interpVal >= 1d | interpVal < 0d)

src/Avalonia.Base/Utilities/MathUtilities.cs

@@ -159,6 +159,11 @@ namespace Avalonia.Utilities
         /// <returns>The clamped value.</returns>
         public static int Clamp(int val, int min, int max)
         {
+            if (min > max)
+            {
+                throw new ArgumentException($"{min} cannot be greater than {max}.");
+            }
+
             if (val < min)
             {
                 return min;

src/Avalonia.Base/ValueStore.cs

@@ -57,7 +57,8 @@ namespace Avalonia
                 {
                     if (priority == (int)BindingPriority.LocalValue)
                     {
-                        _propertyValues.SetValue(property, Validate(property, value));
+                        Validate(property, ref value);
+                        _propertyValues.SetValue(property, value);
                         Changed(property, priority, v, value);
                         return;
                     }
@@ -78,7 +79,8 @@ namespace Avalonia
 
                 if (priority == (int)BindingPriority.LocalValue)
                 {
-                    _propertyValues.AddValue(property, Validate(property, value));
+                    Validate(property, ref value);
+                    _propertyValues.AddValue(property, value);
                     Changed(property, priority, AvaloniaProperty.UnsetValue, value);
                     return;
                 }
@@ -166,16 +168,14 @@ namespace Avalonia
                 validate2);
         }
 
-        private object Validate(AvaloniaProperty property, object value)
+        private void Validate(AvaloniaProperty property, ref object value)
         {
             var validate = ((IStyledPropertyAccessor)property).GetValidationFunc(_owner.GetType());
 
             if (validate != null && value != AvaloniaProperty.UnsetValue)
             {
-                return validate(_owner, value);
+                value = validate(_owner, value);
             }
-
-            return value;
         }
 
         private DeferredSetter<T> GetDeferredSetter<T>(AvaloniaProperty property)

src/Avalonia.Controls/AppBuilderBase.cs

@@ -125,9 +125,8 @@ namespace Avalonia.Controls
             });
             
             // Copy-pasted because we can't call extension methods due to generic constraints
-            var lifetime = new ClassicDesktopStyleApplicationLifetime(Instance) {ShutdownMode = ShutdownMode.OnMainWindowClose};
+            var lifetime = new ClassicDesktopStyleApplicationLifetime() {ShutdownMode = ShutdownMode.OnMainWindowClose};
-            Instance.ApplicationLifetime = lifetime;
+            SetupWithLifetime(lifetime);
-            SetupWithoutStarting();
             lifetime.Start(Array.Empty<string>());
         }
 

src/Avalonia.Controls/ApplicationLifetimes/ClassicDesktopStyleApplicationLifetime.cs

@@ -5,12 +5,12 @@ using System.Threading;
 using Avalonia.Controls;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Interactivity;
+using Avalonia.Threading;
 
 namespace Avalonia.Controls.ApplicationLifetimes
 {
     public class ClassicDesktopStyleApplicationLifetime : IClassicDesktopStyleApplicationLifetime, IDisposable
     {
-        private readonly Application _app;
         private int _exitCode;
         private CancellationTokenSource _cts;
         private bool _isShuttingDown;
@@ -34,12 +34,11 @@ namespace Avalonia.Controls.ApplicationLifetimes
             _activeLifetime?._windows.Add((Window)sender);
         }
 
-        public ClassicDesktopStyleApplicationLifetime(Application app)
+        public ClassicDesktopStyleApplicationLifetime()
         {
             if (_activeLifetime != null)
                 throw new InvalidOperationException(
                     "Can not have multiple active ClassicDesktopStyleApplicationLifetime instances and the previously created one was not disposed");
-            _app = app;
             _activeLifetime = this;
         }
         
@@ -103,7 +102,7 @@ namespace Avalonia.Controls.ApplicationLifetimes
             Startup?.Invoke(this, new ControlledApplicationLifetimeStartupEventArgs(args));
             _cts = new CancellationTokenSource();
             MainWindow?.Show();
-            _app.Run(_cts.Token);
+            Dispatcher.UIThread.MainLoop(_cts.Token);
             Environment.ExitCode = _exitCode;
             return _exitCode;
         }
@@ -124,7 +123,7 @@ namespace Avalonia
             this T builder, string[] args, ShutdownMode shutdownMode = ShutdownMode.OnLastWindowClose)
             where T : AppBuilderBase<T>, new()
         {
-            var lifetime = new ClassicDesktopStyleApplicationLifetime(builder.Instance) {ShutdownMode = shutdownMode};
+            var lifetime = new ClassicDesktopStyleApplicationLifetime() {ShutdownMode = shutdownMode};
             builder.SetupWithLifetime(lifetime);
             return lifetime.Start(args);
         }

src/Avalonia.Controls/AutoCompleteBox.cs

@@ -704,7 +704,7 @@ namespace Avalonia.Controls
                 added.Add(e.NewValue);
             }
 
-            OnSelectionChanged(new SelectionChangedEventArgs(SelectionChangedEvent, removed, added));
+            OnSelectionChanged(new SelectionChangedEventArgs(SelectionChangedEvent, added, removed));
         }
 
         /// <summary>

src/Avalonia.Controls/ColumnDefinition.cs

@@ -26,6 +26,16 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<GridLength> WidthProperty =
             AvaloniaProperty.Register<ColumnDefinition, GridLength>(nameof(Width), new GridLength(1, GridUnitType.Star));
 
+        /// <summary>
+        /// Initializes static members of the <see cref="ColumnDefinition"/> class.
+        /// </summary>
+        static ColumnDefinition()
+        {
+            AffectsParentMeasure(MinWidthProperty, MaxWidthProperty);
+
+            WidthProperty.Changed.AddClassHandler<DefinitionBase>(OnUserSizePropertyChanged);
+        }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="ColumnDefinition"/> class.
         /// </summary>
@@ -68,7 +78,6 @@ namespace Avalonia.Controls
             }
             set
             {
-                Parent?.InvalidateMeasure();
                 SetValue(MaxWidthProperty, value);
             }
         }
@@ -84,7 +93,6 @@ namespace Avalonia.Controls
             }
             set
             {
-                Parent?.InvalidateMeasure();
                 SetValue(MinWidthProperty, value);
             }
         }
@@ -100,7 +108,6 @@ namespace Avalonia.Controls
             }
             set
             {
-                Parent?.InvalidateMeasure();
                 SetValue(WidthProperty, value);
             }
         }

src/Avalonia.Controls/DefinitionBase.cs

@@ -7,9 +7,6 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
-
-using Avalonia;
-using Avalonia.Collections;
 using Avalonia.Utilities;
 
 namespace Avalonia.Controls
@@ -50,6 +47,8 @@ namespace Avalonia.Controls
                     }
                 }
             }
+
+            Parent?.InvalidateMeasure();
         }
 
         /// <summary>
@@ -63,6 +62,8 @@ namespace Avalonia.Controls
                 _sharedState.RemoveMember(this);
                 _sharedState = null;
             }
+
+            Parent?.InvalidateMeasure();
         }
 
         /// <summary>
@@ -114,6 +115,36 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <remarks>
+        /// Notifies parent <see cref="Grid"/> or size scope that definition size has been changed.
+        /// </remarks>
+        internal static void OnUserSizePropertyChanged(DefinitionBase definition, AvaloniaPropertyChangedEventArgs e)
+        {
+            if (definition.Parent == null)
+            {
+                return;
+            }
+
+            if (definition._sharedState != null)
+            {
+                definition._sharedState.Invalidate();
+            }
+            else
+            {
+                GridUnitType oldUnitType = ((GridLength)e.OldValue).GridUnitType;
+                GridUnitType newUnitType = ((GridLength)e.NewValue).GridUnitType;
+
+                if (oldUnitType != newUnitType)
+                {
+                    definition.Parent.Invalidate();
+                }
+                else
+                {
+                    definition.Parent.InvalidateMeasure();
+                }
+            }
+        }
+
         /// <summary>
         /// Returns <c>true</c> if this definition is a part of shared group.
         /// </summary>
@@ -730,5 +761,22 @@ namespace Avalonia.Controls
             SharedSizeGroupProperty.Changed.AddClassHandler<DefinitionBase>(OnSharedSizeGroupPropertyChanged);
             PrivateSharedSizeScopeProperty.Changed.AddClassHandler<DefinitionBase>(OnPrivateSharedSizeScopePropertyChanged);
         }
+
+        /// <summary>
+        /// Marks a property on a definition as affecting the parent grid's measurement.
+        /// </summary>
+        /// <param name="properties">The properties.</param>
+        protected static void AffectsParentMeasure(params AvaloniaProperty[] properties)
+        {
+            void Invalidate(AvaloniaPropertyChangedEventArgs e)
+            {
+                (e.Sender as DefinitionBase)?.Parent?.InvalidateMeasure();
+            }
+
+            foreach (var property in properties)
+            {
+                property.Changed.Subscribe(Invalidate);
+            }
+        }
     }
 }

src/Avalonia.Controls/DesktopApplicationExtensions.cs

@@ -50,6 +50,7 @@ namespace Avalonia.Controls
         /// On desktop-style platforms runs the application's main loop with custom CancellationToken
         /// without setting a lifetime.
         /// </summary>
+        /// <param name="app">The application.</param>
         /// <param name="token">The token to track.</param>
         public static void Run(this Application app, CancellationToken token)
         {

src/Avalonia.Controls/Generators/TabItemContainerGenerator.cs

@@ -48,11 +48,6 @@ namespace Avalonia.Controls.Generators
                 tabItem[~ContentControl.ContentTemplateProperty] = Owner[~TabControl.ContentTemplateProperty];
             }
 
-            if (tabItem.Content == null)
-            {
-                tabItem[~ContentControl.ContentProperty] = tabItem[~StyledElement.DataContextProperty];
-            }
-
             return tabItem;
         }
     }

src/Avalonia.Controls/Grid.cs

@@ -6,6 +6,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
@@ -178,6 +179,7 @@ namespace Avalonia.Controls
                 if (_data == null) { _data = new ExtendedData(); }
                 _data.ColumnDefinitions = value;
                 _data.ColumnDefinitions.Parent = this;
+                InvalidateMeasure();
             }
         }
 
@@ -198,6 +200,7 @@ namespace Avalonia.Controls
                 if (_data == null) { _data = new ExtendedData(); }
                 _data.RowDefinitions = value;
                 _data.RowDefinitions.Parent = this;
+                InvalidateMeasure();
             }
         }
 
@@ -569,6 +572,15 @@ namespace Avalonia.Controls
             return (arrangeSize);
         }
 
+        /// <summary>
+        /// <see cref="Panel.ChildrenChanged"/>
+        /// </summary>
+        protected override void ChildrenChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            CellsStructureDirty = true;
+            base.ChildrenChanged(sender, e);
+        }
+
         /// <summary>
         /// Invalidates grid caches and makes the grid dirty for measure.
         /// </summary>

src/Avalonia.Controls/ItemsControl.cs

@@ -359,6 +359,12 @@ namespace Avalonia.Controls
             UpdateItemCount();
             RemoveControlItemsFromLogicalChildren(oldValue);
             AddControlItemsToLogicalChildren(newValue);
+
+            if (Presenter != null)
+            {
+                Presenter.Items = newValue;
+            }
+
             SubscribeToItems(newValue);
         }
 
@@ -370,6 +376,8 @@ namespace Avalonia.Controls
         /// <param name="e">The event args.</param>
         protected virtual void ItemsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
         {
+            UpdateItemCount();
+
             switch (e.Action)
             {
                 case NotifyCollectionChangedAction.Add:
@@ -381,7 +389,7 @@ namespace Avalonia.Controls
                     break;
             }
 
-            UpdateItemCount();
+            Presenter?.ItemsChanged(e);
 
             var collection = sender as ICollection;
             PseudoClasses.Set(":empty", collection == null || collection.Count == 0);

src/Avalonia.Controls/Presenters/IItemsPresenter.cs

@@ -1,12 +1,19 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using System.Collections;
+using System.Collections.Specialized;
+
 namespace Avalonia.Controls.Presenters
 {
     public interface IItemsPresenter : IPresenter
     {
+        IEnumerable Items { get; set; }
+
         IPanel Panel { get; }
 
+        void ItemsChanged(NotifyCollectionChangedEventArgs e);
+
         void ScrollIntoView(object item);
     }
 }

src/Avalonia.Controls/Presenters/ItemsPresenterBase.cs

@@ -63,7 +63,7 @@ namespace Avalonia.Controls.Presenters
                 _itemsSubscription?.Dispose();
                 _itemsSubscription = null;
 
-                if (_createdPanel && value is INotifyCollectionChanged incc)
+                if (!IsHosted && _createdPanel && value is INotifyCollectionChanged incc)
                 {
                     _itemsSubscription = incc.WeakSubscribe(ItemsCollectionChanged);
                 }
@@ -130,6 +130,8 @@ namespace Avalonia.Controls.Presenters
             private set;
         }
 
+        protected bool IsHosted => TemplatedParent is IItemsPresenterHost;
+
         /// <inheritdoc/>
         public override sealed void ApplyTemplate()
         {
@@ -144,6 +146,15 @@ namespace Avalonia.Controls.Presenters
         {
         }
 
+        /// <inheritdoc/>
+        void IItemsPresenter.ItemsChanged(NotifyCollectionChangedEventArgs e)
+        {
+            if (Panel != null)
+            {
+                ItemsChanged(e);
+            }
+        }
+
         /// <summary>
         /// Creates the <see cref="ItemContainerGenerator"/> for the control.
         /// </summary>
@@ -215,7 +226,7 @@ namespace Avalonia.Controls.Presenters
 
             _createdPanel = true;
 
-            if (_itemsSubscription == null && Items is INotifyCollectionChanged incc)
+            if (!IsHosted && _itemsSubscription == null && Items is INotifyCollectionChanged incc)
             {
                 _itemsSubscription = incc.WeakSubscribe(ItemsCollectionChanged);
             }

src/Avalonia.Controls/Primitives/PopupRoot.cs

@@ -41,6 +41,8 @@ namespace Avalonia.Controls.Primitives
         /// <summary>
         /// Initializes a new instance of the <see cref="PopupRoot"/> class.
         /// </summary>
+        /// <param name="parent">The popup parent.</param>
+        /// <param name="impl">The popup implementation.</param>
         /// <param name="dependencyResolver">
         /// The dependency resolver to use. If null the default dependency resolver will be used.
         /// </param>

src/Avalonia.Controls/Primitives/SelectingItemsControl.cs

@@ -302,13 +302,24 @@ namespace Avalonia.Controls.Primitives
         /// <inheritdoc/>
         protected override void ItemsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
         {
-            base.ItemsCollectionChanged(sender, e);
-
             if (_updateCount > 0)
             {
+                base.ItemsCollectionChanged(sender, e);
                 return;
             }
 
+            switch (e.Action)
+            {
+                case NotifyCollectionChangedAction.Add:
+                    _selection.ItemsInserted(e.NewStartingIndex, e.NewItems.Count);
+                    break;
+                case NotifyCollectionChangedAction.Remove:
+                    _selection.ItemsRemoved(e.OldStartingIndex, e.OldItems.Count);
+                    break;
+            }
+
+            base.ItemsCollectionChanged(sender, e);
+
             switch (e.Action)
             {
                 case NotifyCollectionChangedAction.Add:
@@ -318,14 +329,12 @@ namespace Avalonia.Controls.Primitives
                     }
                     else
                     {
-                        _selection.ItemsInserted(e.NewStartingIndex, e.NewItems.Count);
                         UpdateSelectedItem(_selection.First(), false);
                     }
 
                     break;
 
                 case NotifyCollectionChangedAction.Remove:
-                    _selection.ItemsRemoved(e.OldStartingIndex, e.OldItems.Count);
                     UpdateSelectedItem(_selection.First(), false);
                     ResetSelectedItems();
                     break;
@@ -1088,9 +1097,15 @@ namespace Avalonia.Controls.Primitives
                 }
                 else
                 {
-                    SelectedIndex = _updateSelectedIndex != int.MinValue ?
+                    if (_updateSelectedIndex != int.MinValue)
-                        _updateSelectedIndex :
+                    {
-                        AlwaysSelected ? 0 : -1;
+                        SelectedIndex = _updateSelectedIndex;
+                    }
+
+                    if (AlwaysSelected && SelectedIndex == -1)
+                    {
+                        SelectedIndex = 0;
+                    }
                 }
             }
         }

src/Avalonia.Controls/RowDefinition.cs

@@ -26,6 +26,16 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<GridLength> HeightProperty =
             AvaloniaProperty.Register<RowDefinition, GridLength>(nameof(Height), new GridLength(1, GridUnitType.Star));
 
+        /// <summary>
+        /// Initializes static members of the <see cref="RowDefinition"/> class.
+        /// </summary>
+        static RowDefinition()
+        {
+            AffectsParentMeasure(MaxHeightProperty, MinHeightProperty);
+
+            HeightProperty.Changed.AddClassHandler<DefinitionBase>(OnUserSizePropertyChanged);
+        }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="RowDefinition"/> class.
         /// </summary>
@@ -68,7 +78,6 @@ namespace Avalonia.Controls
             }
             set
             {
-                Parent?.InvalidateMeasure();
                 SetValue(MaxHeightProperty, value);
             }
         }
@@ -84,7 +93,6 @@ namespace Avalonia.Controls
             }
             set
             {
-                Parent?.InvalidateMeasure();
                 SetValue(MinHeightProperty, value);
             }
         }
@@ -100,7 +108,6 @@ namespace Avalonia.Controls
             }
             set
             {
-                Parent?.InvalidateMeasure();
                 SetValue(HeightProperty, value);
             }
         }

src/Avalonia.Controls/ToolTipService.cs

@@ -1,6 +1,7 @@
 using System;
 using Avalonia.Input;
 using Avalonia.Threading;
+using Avalonia.VisualTree;
 
 namespace Avalonia.Controls
 {
@@ -79,7 +80,10 @@ namespace Avalonia.Controls
         {
             StopTimer();
 
-            ToolTip.SetIsOpen(control, true);
+            if ((control as IVisual).IsAttachedToVisualTree)
+            {
+                ToolTip.SetIsOpen(control, true);
+            }
         }
 
         private void Close(Control control)

src/Avalonia.Controls/WrapPanel.cs

@@ -42,7 +42,7 @@ namespace Avalonia.Controls
         /// </summary>
         static WrapPanel()
         {
-            AffectsMeasure<WrapPanel>(OrientationProperty);
+            AffectsMeasure<WrapPanel>(OrientationProperty, ItemWidthProperty, ItemHeightProperty);
         }
 
         /// <summary>

src/Avalonia.Input/MouseDevice.cs

@@ -14,13 +14,14 @@ namespace Avalonia.Input
     /// <summary>
     /// Represents a mouse device.
     /// </summary>
-    public class MouseDevice : IMouseDevice
+    public class MouseDevice : IMouseDevice, IDisposable
     {
         private int _clickCount;
         private Rect _lastClickRect;
         private ulong _lastClickTime;
 
         private readonly Pointer _pointer;
+        private bool _disposed;
 
         public MouseDevice(Pointer pointer = null)
         {
@@ -126,7 +127,9 @@ namespace Avalonia.Input
         {
             Contract.Requires<ArgumentNullException>(e != null);
 
-            var mouse = (IMouseDevice)e.Device;
+            var mouse = (MouseDevice)e.Device;
+            if(mouse._disposed)
+                return;
 
             Position = e.Root.PointToScreen(e.Position);
             var props = CreateProperties(e);
@@ -441,5 +444,11 @@ namespace Avalonia.Input
                 el = (IInputElement)el.VisualParent;
             }
         }
+
+        public void Dispose()
+        {
+            _disposed = true;
+            _pointer?.Dispose();
+        }
     }
 }

src/Avalonia.Input/Pointer.cs

@@ -37,7 +37,7 @@ namespace Avalonia.Input
         {
             if (Captured != null)
                 Captured.DetachedFromVisualTree -= OnCaptureDetached;
-            var oldCapture = control;
+            var oldCapture = Captured;
             Captured = control;
             PlatformCapture(control);
             if (oldCapture != null)

src/Avalonia.Input/TouchDevice.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using Avalonia.Input.Raw;
@@ -11,10 +12,11 @@ namespace Avalonia.Input
     /// This class is supposed to be used on per-toplevel basis, don't use a shared one
     /// </remarks>
     /// </summary>
-    public class TouchDevice : IInputDevice
+    public class TouchDevice : IInputDevice, IDisposable
     {
-        Dictionary<long, Pointer> _pointers = new Dictionary<long, Pointer>();
+        private readonly Dictionary<long, Pointer> _pointers = new Dictionary<long, Pointer>();
-
+        private bool _disposed;
+        
         KeyModifiers GetKeyModifiers(RawInputModifiers modifiers) =>
             (KeyModifiers)(modifiers & RawInputModifiers.KeyboardMask);
 
@@ -28,6 +30,8 @@ namespace Avalonia.Input
         
         public void ProcessRawEvent(RawInputEventArgs ev)
         {
+            if(_disposed)
+                return;
             var args = (RawTouchEventArgs)ev;
             if (!_pointers.TryGetValue(args.TouchPointId, out var pointer))
             {
@@ -82,6 +86,17 @@ namespace Avalonia.Input
 
             
         }
+
+        public void Dispose()
+        {
+            if(_disposed)
+                return;
+            var values = _pointers.Values.ToList();
+            _pointers.Clear();
+            _disposed = true;
+            foreach (var p in values)
+                p.Dispose();
+        }
         
     }
 }

src/Avalonia.Native/AvaloniaNativePlatform.cs

@@ -95,7 +95,6 @@ namespace Avalonia.Native
                 .Bind<IStandardCursorFactory>().ToConstant(new CursorFactory(_factory.CreateCursorFactory()))
                 .Bind<IPlatformIconLoader>().ToSingleton<IconLoader>()
                 .Bind<IKeyboardDevice>().ToConstant(KeyboardDevice)
-                .Bind<IMouseDevice>().ToConstant(MouseDevice)
                 .Bind<IPlatformSettings>().ToConstant(this)
                 .Bind<IWindowingPlatform>().ToConstant(this)
                 .Bind<IClipboard>().ToConstant(new ClipboardImpl(_factory.CreateClipboard()))

src/Avalonia.Native/WindowImplBase.cs

@@ -24,7 +24,7 @@ namespace Avalonia.Native
         private object _syncRoot = new object();
         private bool _deferredRendering = false;
         private bool _gpu = false;
-        private readonly IMouseDevice _mouse;
+        private readonly MouseDevice _mouse;
         private readonly IKeyboardDevice _keyboard;
         private readonly IStandardCursorFactory _cursorFactory;
         private Size _savedLogicalSize;
@@ -38,7 +38,7 @@ namespace Avalonia.Native
             _deferredRendering = opts.UseDeferredRendering;
 
             _keyboard = AvaloniaLocator.Current.GetService<IKeyboardDevice>();
-            _mouse = AvaloniaLocator.Current.GetService<IMouseDevice>();
+            _mouse = new MouseDevice();
             _cursorFactory = AvaloniaLocator.Current.GetService<IStandardCursorFactory>();
         }
 
@@ -142,6 +142,7 @@ namespace Avalonia.Native
                 {
                     n?.Dispose();
                 }
+                _parent._mouse.Dispose();
             }
 
             void IAvnWindowBaseEvents.Activated() => _parent.Activated?.Invoke();

src/Avalonia.Themes.Default/ContextMenu.xaml

@@ -11,19 +11,11 @@
               BorderThickness="{TemplateBinding BorderThickness}"
               Padding="{TemplateBinding Padding}">
           <ScrollViewer>
-            <Panel>
               <ItemsPresenter Name="PART_ItemsPresenter"
                               Items="{TemplateBinding Items}"
                               ItemsPanel="{TemplateBinding ItemsPanel}"
                               ItemTemplate="{TemplateBinding ItemTemplate}"
                               KeyboardNavigation.TabNavigation="Continue"/>
-              <Rectangle Name="iconSeparator"
-                         Fill="{DynamicResource ThemeControlMidBrush}"
-                         HorizontalAlignment="Left"
-                         IsHitTestVisible="False"
-                         Margin="29,2,0,2"
-                         Width="1"/>
-              </Panel>
           </ScrollViewer>
       </Border>
     </ControlTemplate>

src/Avalonia.Themes.Default/MenuItem.xaml

@@ -4,14 +4,14 @@
   <Style Selector="MenuItem">
     <Setter Property="Background" Value="Transparent"/>
     <Setter Property="BorderThickness" Value="1"/>
-    <Setter Property="Padding" Value="6,0"/>
+    <Setter Property="Padding" Value="6 0"/>
     <Setter Property="Template">
       <ControlTemplate>
         <Border Name="root"
                 Background="{TemplateBinding Background}"
                 BorderBrush="{TemplateBinding BorderBrush}"
                 BorderThickness="{TemplateBinding BorderThickness}">
-          <Grid ColumnDefinitions="22,13,*,20">
+          <Grid ColumnDefinitions="20,5,*,20">
             <ContentPresenter Name="icon"
                               Content="{TemplateBinding Icon}"
                               Width="16"
@@ -50,20 +50,12 @@
               <Border Background="{TemplateBinding Background}"
                       BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                       BorderThickness="{TemplateBinding BorderThickness}">
-                <ScrollViewer>
+                <ScrollViewer>                  
-                  <Panel>
                     <ItemsPresenter Name="PART_ItemsPresenter"
                                     Items="{TemplateBinding Items}"
                                     ItemsPanel="{TemplateBinding ItemsPanel}"
                                     ItemTemplate="{TemplateBinding ItemTemplate}"
-                                    Margin="2"/>
+                                    Margin="4 2"/>                                      
-                    <Rectangle Name="iconSeparator"
-                               Fill="{DynamicResource ThemeControlMidBrush}"
-                               HorizontalAlignment="Left"
-                               IsHitTestVisible="False"
-                               Margin="29,2,0,2"
-                               Width="1"/>
-                  </Panel>
                 </ScrollViewer>
               </Border>
             </Popup>
@@ -77,13 +69,14 @@
     <Setter Property="Template">
       <ControlTemplate>
         <Separator Background="{DynamicResource ThemeControlMidBrush}"
-                   Margin="29,1,0,1"
+                   Margin="20,1,0,1"
                    Height="1"/>
       </ControlTemplate>
     </Setter>
   </Style>
 
   <Style Selector="Menu > MenuItem">
+    <Setter Property="Padding" Value="6 0"/>
     <Setter Property="Template">
       <ControlTemplate>
         <Border Name="root"
@@ -108,19 +101,11 @@
                       BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                       BorderThickness="{TemplateBinding BorderThickness}">
                 <ScrollViewer>
-                  <Panel>
+                  <ItemsPresenter Name="PART_ItemsPresenter"
-                    <ItemsPresenter Name="PART_ItemsPresenter"
                                     Items="{TemplateBinding Items}"
                                     ItemsPanel="{TemplateBinding ItemsPanel}"
                                     ItemTemplate="{TemplateBinding ItemTemplate}"
                                     Margin="2"/>
-                    <Rectangle Name="iconSeparator"
-                               Fill="{DynamicResource ThemeControlMidBrush}"
-                               HorizontalAlignment="Left"
-                               IsHitTestVisible="False"
-                               Margin="29,2,0,2"
-                               Width="1"/>
-                  </Panel>
                 </ScrollViewer>
               </Border>
             </Popup>

src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs

@@ -51,7 +51,7 @@ namespace Avalonia.Rendering.SceneGraph
                 UpdateSize(scene);
             }
 
-            if (visual.VisualRoot != null)
+            if (visual.VisualRoot == scene.Root.Visual)
             {
                 if (node?.Parent != null &&
                     visual.VisualParent != null &&

src/Avalonia.X11/X11Platform.cs

@@ -19,9 +19,7 @@ namespace Avalonia.X11
     class AvaloniaX11Platform : IWindowingPlatform
     {
         private Lazy<KeyboardDevice> _keyboardDevice = new Lazy<KeyboardDevice>(() => new KeyboardDevice());
-        private Lazy<MouseDevice> _mouseDevice = new Lazy<MouseDevice>(() => new MouseDevice());
         public KeyboardDevice KeyboardDevice => _keyboardDevice.Value;
-        public MouseDevice MouseDevice => _mouseDevice.Value;
         public Dictionary<IntPtr, Action<XEvent>> Windows = new Dictionary<IntPtr, Action<XEvent>>();
         public XI2Manager XI2;
         public X11Info Info { get; private set; }

src/Avalonia.X11/X11Window.cs

@@ -32,7 +32,8 @@ namespace Avalonia.X11
         private PixelPoint? _configurePoint;
         private bool _triggeredExpose;
         private IInputRoot _inputRoot;
-        private readonly IMouseDevice _mouse;
+        private readonly MouseDevice _mouse;
+        private readonly TouchDevice _touch;
         private readonly IKeyboardDevice _keyboard;
         private PixelPoint? _position;
         private PixelSize _realSize;
@@ -57,7 +58,8 @@ namespace Avalonia.X11
             _platform = platform;
             _popup = popupParent != null;
             _x11 = platform.Info;
-            _mouse = platform.MouseDevice;
+            _mouse = new MouseDevice();
+            _touch = new TouchDevice();
             _keyboard = platform.KeyboardDevice;
 
             var glfeature = AvaloniaLocator.Current.GetService<IWindowingPlatformGlFeature>();
@@ -702,6 +704,8 @@ namespace Avalonia.X11
                 _platform.XI2?.OnWindowDestroyed(_handle);
                 _handle = IntPtr.Zero;
                 Closed?.Invoke();
+                _mouse.Dispose();
+                _touch.Dispose();
             }
             
             if (_useRenderWindow && _renderHandle != IntPtr.Zero)
@@ -830,6 +834,8 @@ namespace Avalonia.X11
         }
 
         public IMouseDevice MouseDevice => _mouse;
+        public TouchDevice TouchDevice => _touch;
+
         public IPopupImpl CreatePopup() 
             => _platform.Options.OverlayPopups ? null : new X11Window(_platform, this);
 

src/Avalonia.X11/XI2Manager.cs

@@ -92,8 +92,6 @@ namespace Avalonia.X11
         
         private PointerDeviceInfo _pointerDevice;
         private AvaloniaX11Platform _platform;
-        private readonly TouchDevice _touchDevice = new TouchDevice();
-
 
         public bool Init(AvaloniaX11Platform platform)
         {
@@ -198,7 +196,7 @@ namespace Avalonia.X11
                     (ev.Type == XiEventType.XI_TouchUpdate ?
                         RawPointerEventType.TouchUpdate :
                         RawPointerEventType.TouchEnd);
-                client.ScheduleInput(new RawTouchEventArgs(_touchDevice,
+                client.ScheduleInput(new RawTouchEventArgs(client.TouchDevice,
                     ev.Timestamp, client.InputRoot, type, ev.Position, ev.Modifiers, ev.Detail));
                 return;
             }
@@ -232,10 +230,10 @@ namespace Avalonia.X11
                 }
 
                 if (scrollDelta != default)
-                    client.ScheduleInput(new RawMouseWheelEventArgs(_platform.MouseDevice, ev.Timestamp,
+                    client.ScheduleInput(new RawMouseWheelEventArgs(client.MouseDevice, ev.Timestamp,
                         client.InputRoot, ev.Position, scrollDelta, ev.Modifiers));
                 if (_pointerDevice.HasMotion(ev))
-                    client.ScheduleInput(new RawPointerEventArgs(_platform.MouseDevice, ev.Timestamp, client.InputRoot,
+                    client.ScheduleInput(new RawPointerEventArgs(client.MouseDevice, ev.Timestamp, client.InputRoot,
                         RawPointerEventType.Move, ev.Position, ev.Modifiers));
             }
 
@@ -248,7 +246,7 @@ namespace Avalonia.X11
                     : ev.Button == 3 ? (down ? RawPointerEventType.RightButtonDown : RawPointerEventType.RightButtonUp)
                     : (RawPointerEventType?)null;
                 if (type.HasValue)
-                    client.ScheduleInput(new RawPointerEventArgs(_platform.MouseDevice, ev.Timestamp, client.InputRoot,
+                    client.ScheduleInput(new RawPointerEventArgs(client.MouseDevice, ev.Timestamp, client.InputRoot,
                         type.Value, ev.Position, ev.Modifiers));
             }
             
@@ -310,5 +308,7 @@ namespace Avalonia.X11
     {
         IInputRoot InputRoot { get; }
         void ScheduleInput(RawInputEventArgs args);
+        IMouseDevice MouseDevice { get; }
+        TouchDevice TouchDevice { get; }
     }
 }

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

@@ -11,19 +11,11 @@ namespace Avalonia.Win32.Input
 {
     class WindowsMouseDevice : MouseDevice
     {
-        public static WindowsMouseDevice Instance { get; } = new WindowsMouseDevice();
-
         public WindowsMouseDevice() : base(new WindowsMousePointer())
         {
             
         }
         
-        public WindowImpl CurrentWindow
-        {
-            get;
-            set;
-        }
-
         class WindowsMousePointer : Pointer
         {
             public WindowsMousePointer() : base(Pointer.GetNextFreeId(),PointerType.Mouse, true)

src/Windows/Avalonia.Win32/WindowImpl.cs

@@ -30,6 +30,7 @@ namespace Avalonia.Win32
         private IntPtr _hwnd;
         private bool _multitouch;
         private TouchDevice _touchDevice = new TouchDevice();
+        private MouseDevice _mouseDevice = new WindowsMouseDevice();
         private IInputRoot _owner;
         private ManagedDeferredRendererLock _rendererLock = new ManagedDeferredRendererLock();
         private bool _trackingMouse;
@@ -205,7 +206,7 @@ namespace Avalonia.Win32
             }
         }
 
-        public IMouseDevice MouseDevice => WindowsMouseDevice.Instance;
+        public IMouseDevice MouseDevice => _mouseDevice;
 
         public WindowState WindowState
         {
@@ -333,7 +334,7 @@ namespace Avalonia.Win32
 
         public void BeginMoveDrag(PointerPressedEventArgs e)
         {
-            WindowsMouseDevice.Instance.Capture(null);
+            _mouseDevice.Capture(null);
             UnmanagedMethods.DefWindowProc(_hwnd, (int)UnmanagedMethods.WindowsMessage.WM_NCLBUTTONDOWN,
                 new IntPtr((int)UnmanagedMethods.HitTestValues.HTCAPTION), IntPtr.Zero);
             e.Pointer.Capture(null);
@@ -356,7 +357,7 @@ namespace Avalonia.Win32
 #if USE_MANAGED_DRAG
             _managedDrag.BeginResizeDrag(edge, ScreenToClient(MouseDevice.Position));
 #else
-            WindowsMouseDevice.Instance.Capture(null);
+            _mouseDevice.Capture(null);
             UnmanagedMethods.DefWindowProc(_hwnd, (int)UnmanagedMethods.WindowsMessage.WM_NCLBUTTONDOWN,
                 new IntPtr((int)EdgeDic[edge]), IntPtr.Zero);
 #endif
@@ -437,9 +438,7 @@ namespace Avalonia.Win32
             uint timestamp = unchecked((uint)UnmanagedMethods.GetMessageTime());
 
             RawInputEventArgs e = null;
-
+            
-            WindowsMouseDevice.Instance.CurrentWindow = this;
-
             switch ((UnmanagedMethods.WindowsMessage)msg)
             {
                 case UnmanagedMethods.WindowsMessage.WM_ACTIVATE:
@@ -485,6 +484,8 @@ namespace Avalonia.Win32
                         _parent._disabledBy.Remove(this);
                         _parent.UpdateEnabled();
                     }
+                    _mouseDevice.Dispose();
+                    _touchDevice?.Dispose();
                     //Free other resources
                     Dispose();
                     return IntPtr.Zero;
@@ -542,7 +543,7 @@ namespace Avalonia.Win32
                     if(ShouldIgnoreTouchEmulatedMessage())
                         break;
                     e = new RawPointerEventArgs(
-                        WindowsMouseDevice.Instance,
+                        _mouseDevice,
                         timestamp,
                         _owner,
                         msg == (int)UnmanagedMethods.WindowsMessage.WM_LBUTTONDOWN
@@ -559,7 +560,7 @@ namespace Avalonia.Win32
                     if(ShouldIgnoreTouchEmulatedMessage())
                         break;
                     e = new RawPointerEventArgs(
-                        WindowsMouseDevice.Instance,
+                        _mouseDevice,
                         timestamp,
                         _owner,
                         msg == (int)UnmanagedMethods.WindowsMessage.WM_LBUTTONUP
@@ -587,7 +588,7 @@ namespace Avalonia.Win32
                     }
 
                     e = new RawPointerEventArgs(
-                        WindowsMouseDevice.Instance,
+                        _mouseDevice,
                         timestamp,
                         _owner,
                         RawPointerEventType.Move,
@@ -597,7 +598,7 @@ namespace Avalonia.Win32
 
                 case UnmanagedMethods.WindowsMessage.WM_MOUSEWHEEL:
                     e = new RawMouseWheelEventArgs(
-                        WindowsMouseDevice.Instance,
+                        _mouseDevice,
                         timestamp,
                         _owner,
                         PointToClient(PointFromLParam(lParam)),
@@ -606,7 +607,7 @@ namespace Avalonia.Win32
 
                 case UnmanagedMethods.WindowsMessage.WM_MOUSEHWHEEL:
                     e = new RawMouseWheelEventArgs(
-                        WindowsMouseDevice.Instance,
+                        _mouseDevice,
                         timestamp,
                         _owner,
                         PointToClient(PointFromLParam(lParam)),
@@ -616,7 +617,7 @@ namespace Avalonia.Win32
                 case UnmanagedMethods.WindowsMessage.WM_MOUSELEAVE:
                     _trackingMouse = false;
                     e = new RawPointerEventArgs(
-                        WindowsMouseDevice.Instance,
+                        _mouseDevice,
                         timestamp,
                         _owner,
                         RawPointerEventType.LeaveWindow,
@@ -627,7 +628,7 @@ namespace Avalonia.Win32
                 case UnmanagedMethods.WindowsMessage.WM_NCRBUTTONDOWN:
                 case UnmanagedMethods.WindowsMessage.WM_NCMBUTTONDOWN:
                     e = new RawPointerEventArgs(
-                        WindowsMouseDevice.Instance,
+                        _mouseDevice,
                         timestamp,
                         _owner,
                         msg == (int)UnmanagedMethods.WindowsMessage.WM_NCLBUTTONDOWN

tests/Avalonia.Animation.UnitTests/TransitionsTests.cs

@@ -1,14 +1,7 @@
 using System;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Avalonia.Animation;
 using Avalonia.Controls;
-using Avalonia.Styling;
 using Avalonia.UnitTests;
-using Avalonia.Data;
 using Xunit;
-using Avalonia.Animation.Easings;
 
 namespace Avalonia.Animation.UnitTests
 {
@@ -69,5 +62,26 @@ namespace Avalonia.Animation.UnitTests
                 Assert.Equal(0, border.Opacity);
             }
         }
+
+        [Fact]
+        public void TransitionInstance_With_Zero_Duration_Is_Completed_On_First_Tick()
+        {
+            var clock = new MockGlobalClock();
+
+            using (UnitTestApplication.Start(new TestServices(globalClock: clock)))
+            {
+                int i = 0;
+                var inst = new TransitionInstance(clock, TimeSpan.Zero).Subscribe(nextValue =>
+                {
+                    switch (i++)
+                    {
+                        case 0: Assert.Equal(0, nextValue); break;
+                        case 1: Assert.Equal(1d, nextValue); break;
+                    }
+                });
+
+                clock.Pulse(TimeSpan.FromMilliseconds(10));
+            }
+        }
     }
 }

tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Validation.cs

@@ -78,6 +78,18 @@ namespace Avalonia.Base.UnitTests
             Assert.Equal(10, target.GetValue(Class1.AttachedProperty));
         }
 
+        [Fact]
+        public void PropertyChanged_Event_Uses_Coerced_Value()
+        {
+            var inst = new Class1();
+            inst.PropertyChanged += (sender, e) =>
+            {
+                Assert.Equal(10, e.NewValue);
+            };
+
+            inst.SetValue(Class1.QuxProperty, 15);
+        }
+
         private class Class1 : AvaloniaObject
         {
             public static readonly StyledProperty<int> QuxProperty =

tests/Avalonia.Controls.UnitTests/DesktopStyleApplicationLifetimeTests.cs

@@ -16,7 +16,7 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Set_ExitCode_After_Shutdown()
         {
             using (UnitTestApplication.Start(TestServices.MockThreadingInterface))
-            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))    
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())    
             {
                 lifetime.Shutdown(1337);
 
@@ -31,7 +31,7 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Close_All_Remaining_Open_Windows_After_Explicit_Exit_Call()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
-            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
             {
                 var windows = new List<Window> { new Window(), new Window(), new Window(), new Window() };
 
@@ -50,7 +50,7 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Only_Exit_On_Explicit_Exit()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
-            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
             {
                 lifetime.ShutdownMode = ShutdownMode.OnExplicitShutdown;
 
@@ -84,7 +84,7 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Exit_After_MainWindow_Closed()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
-            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
             {
                 lifetime.ShutdownMode = ShutdownMode.OnMainWindowClose;
 
@@ -112,7 +112,7 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Exit_After_Last_Window_Closed()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
-            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
             {
                 lifetime.ShutdownMode = ShutdownMode.OnLastWindowClose;
 
@@ -142,7 +142,7 @@ namespace Avalonia.Controls.UnitTests
         public void Show_Should_Add_Window_To_OpenWindows()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
-            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
             {
                 var window = new Window();
 
@@ -156,7 +156,7 @@ namespace Avalonia.Controls.UnitTests
         public void Window_Should_Be_Added_To_OpenWindows_Only_Once()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
-            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
             {
                 var window = new Window();
 
@@ -174,7 +174,7 @@ namespace Avalonia.Controls.UnitTests
         public void Close_Should_Remove_Window_From_OpenWindows()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
-            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
             {
                 var window = new Window();
 
@@ -197,7 +197,7 @@ namespace Avalonia.Controls.UnitTests
                 windowingPlatform: new MockWindowingPlatform(() => windowImpl.Object));
 
             using (UnitTestApplication.Start(services))
-            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
             {
                 var window = new Window();
 

tests/Avalonia.Controls.UnitTests/GridTests.cs

@@ -1,11 +1,6 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
-using Avalonia.Controls.Primitives;
-using Avalonia.Input;
-using Avalonia.Platform;
-using Avalonia.UnitTests;
-
-using Moq;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -34,7 +29,6 @@ namespace Avalonia.Controls.UnitTests
 
         private Grid CreateGrid(params (string name, GridLength width, double minWidth, double maxWidth)[] columns)
         {
-
             var grid = new Grid();
             foreach (var k in columns.Select(c => new ColumnDefinition
             {
@@ -1178,6 +1172,41 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(0, grids[0].ColumnDefinitions[0].ActualWidth);
         }
 
+        [Fact]
+        public void Size_Group_Definition_Resizes_Are_Tracked()
+        {
+            var grids = new[] {
+                CreateGrid(("A", new GridLength(5, GridUnitType.Pixel)), (null, new GridLength())),
+                CreateGrid(("A", new GridLength(5, GridUnitType.Pixel)), (null, new GridLength())) };
+            var scope = new Grid();
+            foreach (var xgrids in grids)
+                scope.Children.Add(xgrids);
+
+            var root = new Grid();
+            root.UseLayoutRounding = false;
+            root.SetValue(Grid.IsSharedSizeScopeProperty, true);
+            root.Children.Add(scope);
+
+            root.Measure(new Size(50, 50));
+            root.Arrange(new Rect(new Point(), new Point(50, 50)));
+
+            PrintColumnDefinitions(grids[0]);
+            Assert.Equal(5, grids[0].ColumnDefinitions[0].ActualWidth);
+            Assert.Equal(5, grids[1].ColumnDefinitions[0].ActualWidth);
+
+            grids[0].ColumnDefinitions[0].Width = new GridLength(10, GridUnitType.Pixel);
+
+            foreach (Grid grid in grids)
+            {
+                grid.Measure(new Size(50, 50));
+                grid.Arrange(new Rect(new Point(), new Point(50, 50)));
+            }
+
+            PrintColumnDefinitions(grids[0]);
+            Assert.Equal(10, grids[0].ColumnDefinitions[0].ActualWidth);
+            Assert.Equal(10, grids[1].ColumnDefinitions[0].ActualWidth);
+        }
+
         [Fact]
         public void Collection_Changes_Are_Tracked()
         {
@@ -1270,11 +1299,11 @@ namespace Avalonia.Controls.UnitTests
             // grid.Measure(new Size(100, 100));
             // grid.Arrange(new Rect(new Point(), new Point(100, 100)));
             // PrintColumnDefinitions(grid);
-            
+
             // NOTE: THIS IS BROKEN IN WPF
             // all in group are equal to width (MinWidth) of the sizer in the second column
             // Assert.All(grid.ColumnDefinitions.Where(cd => cd.SharedSizeGroup == "A"), cd => Assert.Equal(6 + 1 * 6, cd.ActualWidth));
-            
+
             // NOTE: THIS IS BROKEN IN WPF
             // grid.ColumnDefinitions[2].SharedSizeGroup = null;
 
@@ -1382,6 +1411,245 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(new Size(100, 100), grid.Bounds.Size);
         }
 
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void Changing_Column_Width_Should_Invalidate_Grid(bool setUsingAvaloniaProperty)
+        {
+            var grid = new Grid { ColumnDefinitions = ColumnDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                if (setUsingAvaloniaProperty)
+                    grid.ColumnDefinitions[0][ColumnDefinition.WidthProperty] = new GridLength(5);
+                else
+                    grid.ColumnDefinitions[0].Width = new GridLength(5);
+            });
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void Changing_Column_MinWidth_Should_Invalidate_Grid(bool setUsingAvaloniaProperty)
+        {
+            var grid = new Grid { ColumnDefinitions = ColumnDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                if (setUsingAvaloniaProperty)
+                    grid.ColumnDefinitions[0][ColumnDefinition.MinWidthProperty] = 5;
+                else
+                    grid.ColumnDefinitions[0].MinWidth = 5;
+            });
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void Changing_Column_MaxWidth_Should_Invalidate_Grid(bool setUsingAvaloniaProperty)
+        {
+            var grid = new Grid { ColumnDefinitions = ColumnDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                if (setUsingAvaloniaProperty)
+                    grid.ColumnDefinitions[0][ColumnDefinition.MaxWidthProperty] = 5;
+                else
+                    grid.ColumnDefinitions[0].MaxWidth = 5;
+            });
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void Changing_Row_Height_Should_Invalidate_Grid(bool setUsingAvaloniaProperty)
+        {
+            var grid = new Grid { RowDefinitions = RowDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                if (setUsingAvaloniaProperty)
+                    grid.RowDefinitions[0][RowDefinition.HeightProperty] = new GridLength(5);
+                else
+                    grid.RowDefinitions[0].Height = new GridLength(5);
+            });
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void Changing_Row_MinHeight_Should_Invalidate_Grid(bool setUsingAvaloniaProperty)
+        {
+            var grid = new Grid { RowDefinitions = RowDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                if (setUsingAvaloniaProperty)
+                    grid.RowDefinitions[0][RowDefinition.MinHeightProperty] = 5;
+                else
+                    grid.RowDefinitions[0].MinHeight = 5;
+            });
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void Changing_Row_MaxHeight_Should_Invalidate_Grid(bool setUsingAvaloniaProperty)
+        {
+            var grid = new Grid { RowDefinitions = RowDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                if (setUsingAvaloniaProperty)
+                    grid.RowDefinitions[0][RowDefinition.MaxHeightProperty] = 5;
+                else
+                    grid.RowDefinitions[0].MaxHeight = 5;
+            });
+        }
+
+        [Fact]
+        public void Adding_Column_Should_Invalidate_Grid()
+        {
+            var grid = new Grid { ColumnDefinitions = ColumnDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                grid.ColumnDefinitions.Add(new ColumnDefinition(new GridLength(5)));
+            });
+        }
+
+        [Fact]
+        public void Adding_Row_Should_Invalidate_Grid()
+        {
+            var grid = new Grid { RowDefinitions = RowDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                grid.RowDefinitions.Add(new RowDefinition(new GridLength(5)));
+            });
+        }
+
+        [Fact]
+        public void Replacing_Columns_Should_Invalidate_Grid()
+        {
+            var grid = new Grid { ColumnDefinitions = ColumnDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                grid.ColumnDefinitions = ColumnDefinitions.Parse("2*,1*");
+            });
+        }
+
+        [Fact]
+        public void Replacing_Rows_Should_Invalidate_Grid()
+        {
+            var grid = new Grid { RowDefinitions = RowDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                grid.RowDefinitions = RowDefinitions.Parse("2*,1*");
+            });
+        }
+
+        [Fact]
+        public void Removing_Column_Should_Invalidate_Grid()
+        {
+            var grid = new Grid { ColumnDefinitions = ColumnDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                grid.ColumnDefinitions.RemoveAt(0);
+            });
+        }
+
+        [Fact]
+        public void Removing_Row_Should_Invalidate_Grid()
+        {
+            var grid = new Grid { RowDefinitions = RowDefinitions.Parse("1*,1*") };
+
+            Change_Property_And_Verify_Measure_Requested(grid, () =>
+            {
+                grid.RowDefinitions.RemoveAt(0);
+            });
+        }
+
+        [Fact]
+        public void Removing_Child_Should_Invalidate_Grid_And_Be_Operational()
+        {
+            var grid = new Grid { ColumnDefinitions = ColumnDefinitions.Parse("*,Auto") };
+
+            grid.Children.Add(new Decorator() { [Grid.ColumnProperty] = 0 });
+            grid.Children.Add(new Decorator() { Width = 10, Height = 10, [Grid.ColumnProperty] = 1 });
+
+            var size = new Size(100, 100);
+            grid.Measure(size);
+            grid.Arrange(new Rect(size));
+
+            Assert.True(grid.IsMeasureValid);
+            Assert.True(grid.IsArrangeValid);
+
+            Assert.Equal(90, grid.Children[0].Bounds.Width);
+            Assert.Equal(10, grid.Children[1].Bounds.Width);
+
+            grid.Children.RemoveAt(1);
+
+            Assert.False(grid.IsMeasureValid);
+            Assert.False(grid.IsArrangeValid);
+
+            grid.Measure(size);
+            grid.Arrange(new Rect(size));
+
+            Assert.True(grid.IsMeasureValid);
+            Assert.True(grid.IsArrangeValid);
+
+            Assert.Equal(100, grid.Children[0].Bounds.Width);
+        }
+
+        [Fact]
+        public void Adding_Child_Should_Invalidate_Grid_And_Be_Operational()
+        {
+            var grid = new Grid { ColumnDefinitions = ColumnDefinitions.Parse("*,Auto") };
+
+            grid.Children.Add(new Decorator() { [Grid.ColumnProperty] = 0 });
+
+            var size = new Size(100, 100);
+            grid.Measure(size);
+            grid.Arrange(new Rect(size));
+
+            Assert.True(grid.IsMeasureValid);
+            Assert.True(grid.IsArrangeValid);
+
+            Assert.Equal(100, grid.Children[0].Bounds.Width);
+
+            grid.Children.Add(new Decorator() { Width = 10, Height = 10, [Grid.ColumnProperty] = 1 });
+
+            Assert.False(grid.IsMeasureValid);
+            Assert.False(grid.IsArrangeValid);
+
+            grid.Measure(size);
+            grid.Arrange(new Rect(size));
+
+            Assert.True(grid.IsMeasureValid);
+            Assert.True(grid.IsArrangeValid);
+
+            Assert.Equal(90, grid.Children[0].Bounds.Width);
+            Assert.Equal(10, grid.Children[1].Bounds.Width);
+        }
+
+        private static void Change_Property_And_Verify_Measure_Requested(Grid grid, Action change)
+        {
+            grid.Measure(new Size(100, 100));
+            grid.Arrange(new Rect(grid.DesiredSize));
+
+            Assert.True(grid.IsMeasureValid);
+            Assert.True(grid.IsArrangeValid);
+
+            change();
+
+            Assert.False(grid.IsMeasureValid);
+            Assert.False(grid.IsArrangeValid);
+        }
+
         private class TestControl : Control
         {
             public Size MeasureSize { get; set; }

tests/Avalonia.Controls.UnitTests/ItemsControlTests.cs

@@ -12,6 +12,7 @@ using Xunit;
 using System.Collections.ObjectModel;
 using Avalonia.UnitTests;
 using Avalonia.Input;
+using System.Collections.Generic;
 
 namespace Avalonia.Controls.UnitTests
 {
@@ -104,6 +105,28 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(new[] { child }, target.GetLogicalChildren());
         }
 
+        [Fact]
+        public void Added_Container_Should_Have_LogicalParent_Set_To_ItemsControl()
+        {
+            var item = new Border();
+            var items = new ObservableCollection<Border>();
+
+            var target = new ItemsControl
+            {
+                Template = GetTemplate(),
+                Items = items,
+            };
+
+            var root = new TestRoot(true, target);
+
+            root.Measure(new Size(100, 100));
+            root.Arrange(new Rect(0, 0, 100, 100));
+
+            items.Add(item);
+
+            Assert.Equal(target, item.Parent);
+        }
+
         [Fact]
         public void Control_Item_Should_Be_Removed_From_Logical_Children_Before_ApplyTemplate()
         {
@@ -522,6 +545,36 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void Presenter_Items_Should_Be_In_Sync()
+        {
+            var target = new ItemsControl
+            {
+                Template = GetTemplate(),
+                Items = new object[]
+                {
+                    new Button(),
+                    new Button(),
+                },
+            };
+
+            var root = new TestRoot { Child = target };
+            var otherPanel = new StackPanel();
+
+            target.ApplyTemplate();
+            target.Presenter.ApplyTemplate();
+            
+            target.ItemContainerGenerator.Materialized += (s, e) =>
+            {
+                Assert.IsType<Canvas>(e.Containers[0].Item);
+            };
+
+            target.Items = new[]
+            {
+                new Canvas()
+            };
+        }
+
         private class Item
         {
             public Item(string value)

tests/Avalonia.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs

@@ -1,6 +1,7 @@
 // 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.Collections;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
@@ -14,6 +15,7 @@ using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Markup.Data;
+using Avalonia.Styling;
 using Avalonia.UnitTests;
 using Moq;
 using Xunit;
@@ -23,7 +25,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
     public class SelectingItemsControlTests
     {
         private MouseTestHelper _helper = new MouseTestHelper();
-        
+
         [Fact]
         public void SelectedIndex_Should_Initially_Be_Minus_1()
         {
@@ -168,6 +170,130 @@ namespace Avalonia.Controls.UnitTests.Primitives
             Assert.Equal("B", listBox.SelectedItem);
         }
 
+        [Fact]
+        public void Setting_SelectedIndex_Before_Initialize_Should_Retain()
+        {
+            var listBox = new ListBox
+            {
+                SelectionMode = SelectionMode.Single,
+                Items = new[] { "foo", "bar", "baz" },
+                SelectedIndex = 1
+            };
+
+            listBox.BeginInit();
+
+            listBox.EndInit();
+
+            Assert.Equal(1, listBox.SelectedIndex);
+            Assert.Equal("bar", listBox.SelectedItem);
+        }
+
+        [Fact]
+        public void Setting_SelectedIndex_During_Initialize_Should_Take_Priority_Over_Previous_Value()
+        {
+            var listBox = new ListBox
+            {
+                SelectionMode = SelectionMode.Single,
+                Items = new[] { "foo", "bar", "baz" },
+                SelectedIndex = 2
+            };
+
+            listBox.BeginInit();
+
+            listBox.SelectedIndex = 1;
+
+            listBox.EndInit();
+
+            Assert.Equal(1, listBox.SelectedIndex);
+            Assert.Equal("bar", listBox.SelectedItem);
+        }
+
+        [Fact]
+        public void Setting_SelectedItem_Before_Initialize_Should_Retain()
+        {
+            var listBox = new ListBox
+            {
+                SelectionMode = SelectionMode.Single,
+                Items = new[] { "foo", "bar", "baz" },
+                SelectedItem = "bar"
+            };
+
+            listBox.BeginInit();
+
+            listBox.EndInit();
+
+            Assert.Equal(1, listBox.SelectedIndex);
+            Assert.Equal("bar", listBox.SelectedItem);
+        }
+
+
+        [Fact]
+        public void Setting_SelectedItems_Before_Initialize_Should_Retain()
+        {
+            var listBox = new ListBox
+            {
+                SelectionMode = SelectionMode.Multiple,
+                Items = new[] { "foo", "bar", "baz" },
+            };
+
+            var selected = new[] { "foo", "bar" };
+
+            foreach (var v in selected)
+            {
+                listBox.SelectedItems.Add(v);
+            }
+
+            listBox.BeginInit();
+
+            listBox.EndInit();
+
+            Assert.Equal(selected, listBox.SelectedItems);
+        }
+
+        [Fact]
+        public void Setting_SelectedItems_During_Initialize_Should_Take_Priority_Over_Previous_Value()
+        {
+            var listBox = new ListBox
+            {
+                SelectionMode = SelectionMode.Multiple,
+                Items = new[] { "foo", "bar", "baz" },
+            };
+
+            var selected = new[] { "foo", "bar" };
+
+            foreach (var v in new[] { "bar", "baz" })
+            {
+                listBox.SelectedItems.Add(v);
+            }
+
+            listBox.BeginInit();
+
+            listBox.SelectedItems = new AvaloniaList<object>(selected);
+
+            listBox.EndInit();
+
+            Assert.Equal(selected, listBox.SelectedItems);
+        }
+
+        [Fact]
+        public void Setting_SelectedIndex_Before_Initialize_With_AlwaysSelected_Should_Retain()
+        {
+            var listBox = new ListBox
+            {
+                SelectionMode = SelectionMode.Single | SelectionMode.AlwaysSelected,
+
+                Items = new[] { "foo", "bar", "baz" },
+                SelectedIndex = 1
+            };
+
+            listBox.BeginInit();
+
+            listBox.EndInit();
+
+            Assert.Equal(1, listBox.SelectedIndex);
+            Assert.Equal("bar", listBox.SelectedItem);
+        }
+
         [Fact]
         public void Setting_SelectedIndex_Before_ApplyTemplate_Should_Set_Item_IsSelected_True()
         {
@@ -849,7 +975,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
             var target = new ListBox
             {
                 Template = Template(),
-                Items = new[] { "Foo", "Bar", "Baz", "Foo", "Bar", "Baz"},
+                Items = new[] { "Foo", "Bar", "Baz", "Foo", "Bar", "Baz" },
             };
 
             target.ApplyTemplate();
@@ -980,6 +1106,45 @@ namespace Avalonia.Controls.UnitTests.Primitives
             Assert.True(raised);
         }
 
+        [Fact]
+        public void AutoScrollToSelectedItem_On_Reset_Works()
+        {
+            // Issue #3148
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var items = new ResettingCollection(100);
+
+                var target = new ListBox
+                {
+                    Items = items,
+                    ItemTemplate = new FuncDataTemplate<string>((x, _) =>
+                        new TextBlock
+                        {
+                            Text = x,
+                            Width = 100,
+                            Height = 10
+                        }),
+                    AutoScrollToSelectedItem = true,
+                    VirtualizationMode = ItemVirtualizationMode.Simple,
+                };
+
+                var root = new TestRoot(true, target);
+                root.Measure(new Size(100, 100));
+                root.Arrange(new Rect(0, 0, 100, 100));
+
+                Assert.True(target.Presenter.Panel.Children.Count > 0);
+                Assert.True(target.Presenter.Panel.Children.Count < 100);
+
+                target.SelectedItem = "Item99";
+
+                // #3148 triggered here.
+                items.Reset(new[] { "Item99" });
+
+                Assert.Equal(0, target.SelectedIndex);
+                Assert.Equal(1, target.Presenter.Panel.Children.Count);
+            }
+        }
+
         [Fact]
         public void Can_Set_Both_SelectedItem_And_SelectedItems_During_Initialization()
         {
@@ -1028,6 +1193,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
                     Name = "itemsPresenter",
                     [~ItemsPresenter.ItemsProperty] = control[~ItemsControl.ItemsProperty],
                     [~ItemsPresenter.ItemsPanelProperty] = control[~ItemsControl.ItemsPanelProperty],
+                    [~ItemsPresenter.VirtualizationModeProperty] = control[~ListBox.VirtualizationModeProperty],
                 }.RegisterInNameScope(scope));
         }
 
@@ -1072,5 +1238,24 @@ namespace Avalonia.Controls.UnitTests.Primitives
                 return base.MoveSelection(direction, wrap);
             }
         }
+
+        private class ResettingCollection : List<string>, INotifyCollectionChanged
+        {
+            public ResettingCollection(int itemCount)
+            {
+                AddRange(Enumerable.Range(0, itemCount).Select(x => $"Item{x}"));
+            }
+
+            public void Reset(IEnumerable<string> items)
+            {
+                Clear();
+                AddRange(items);
+                CollectionChanged?.Invoke(
+                    this,
+                    new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
+            }
+
+            public event NotifyCollectionChangedEventHandler CollectionChanged;
+        }
     }
 }

tests/Avalonia.Controls.UnitTests/TabControlTests.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.ObjectModel;
 using System.Linq;
+using Avalonia.Collections;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
@@ -287,6 +288,25 @@ namespace Avalonia.Controls.UnitTests
             Assert.Single(target.GetLogicalChildren(), content);
         }
 
+        [Fact]
+        public void Should_Not_Propagate_DataContext_To_TabItem_Content()
+        {
+            var dataContext = "DataContext";
+
+            var tabItem = new TabItem();
+
+            var target = new TabControl
+            {
+                Template = TabControlTemplate(),
+                DataContext = dataContext,
+                Items = new AvaloniaList<object> { tabItem }
+            };
+
+            ApplyTemplate(target);
+
+            Assert.NotEqual(dataContext, tabItem.Content);
+        }
+
         private IControlTemplate TabControlTemplate()
         {
             return new FuncControlTemplate<TabControl>((parent, scope) =>

tests/Avalonia.Controls.UnitTests/ToolTipTests.cs

@@ -0,0 +1,109 @@
+// 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.Reactive.Disposables;
+using Avalonia.Platform;
+using Avalonia.Threading;
+using Avalonia.UnitTests;
+using Avalonia.VisualTree;
+using Moq;
+using Xunit;
+
+namespace Avalonia.Controls.UnitTests
+{
+    public class TolTipTests
+    {
+        private MouseTestHelper _mouseHelper = new MouseTestHelper();
+
+        [Fact]
+        public void Should_Not_Open_On_Detached_Control()
+        {
+            //issue #3188
+            var control = new Decorator()
+            {
+                [ToolTip.TipProperty] = "Tip",
+                [ToolTip.ShowDelayProperty] = 0
+            };
+
+            Assert.False((control as IVisual).IsAttachedToVisualTree);
+
+            //here in issue #3188 exception is raised
+            _mouseHelper.Enter(control);
+
+            Assert.False(ToolTip.GetIsOpen(control));
+        }
+
+        [Fact]
+        public void Should_Open_On_Pointer_Enter()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var window = new Window();
+
+                var target = new Decorator()
+                {
+                    [ToolTip.TipProperty] = "Tip",
+                    [ToolTip.ShowDelayProperty] = 0
+                };
+
+                window.Content = target;
+
+                window.ApplyTemplate();
+                window.Presenter.ApplyTemplate();
+
+                Assert.True((target as IVisual).IsAttachedToVisualTree);
+
+                _mouseHelper.Enter(target);
+
+                Assert.True(ToolTip.GetIsOpen(target));
+            }
+        }
+
+        [Fact]
+        public void Should_Open_On_Pointer_Enter_With_Delay()
+        {
+            Action timercallback = null;
+            var delay = TimeSpan.Zero;
+
+            var pti = Mock.Of<IPlatformThreadingInterface>(x => x.CurrentThreadIsLoopThread == true);
+
+            Mock.Get(pti)
+                .Setup(v => v.StartTimer(It.IsAny<DispatcherPriority>(), It.IsAny<TimeSpan>(), It.IsAny<Action>()))
+                .Callback<DispatcherPriority, TimeSpan, Action>((priority, interval, tick) =>
+                {
+                    delay = interval;
+                    timercallback = tick;
+                })
+                .Returns(Disposable.Empty);
+
+            using (UnitTestApplication.Start(TestServices.StyledWindow.With(threadingInterface: pti)))
+            {
+                var window = new Window();
+
+                var target = new Decorator()
+                {
+                    [ToolTip.TipProperty] = "Tip",
+                    [ToolTip.ShowDelayProperty] = 1
+                };
+
+                window.Content = target;
+
+                window.ApplyTemplate();
+                window.Presenter.ApplyTemplate();
+
+                Assert.True((target as IVisual).IsAttachedToVisualTree);
+
+                _mouseHelper.Enter(target);
+
+                Assert.Equal(TimeSpan.FromMilliseconds(1), delay);
+                Assert.NotNull(timercallback);
+                Assert.False(ToolTip.GetIsOpen(target));
+
+                timercallback();
+
+                Assert.True(ToolTip.GetIsOpen(target));
+            }
+        }
+    }
+}

tests/Avalonia.Controls.UnitTests/WrapPanelTests.cs

@@ -12,14 +12,14 @@ namespace Avalonia.Controls.UnitTests
         public void Lays_Out_Horizontally_On_Separate_Lines()
         {
             var target = new WrapPanel()
-                         {
+            {
-                            Width = 100,
+                Width = 100,
-                            Children =
+                Children =
                             {
                                 new Border { Height = 50, Width = 100 },
                                 new Border { Height = 50, Width = 100 },
                             }
-                         };
+            };
 
             target.Measure(Size.Infinity);
             target.Arrange(new Rect(target.DesiredSize));
@@ -33,14 +33,14 @@ namespace Avalonia.Controls.UnitTests
         public void Lays_Out_Horizontally_On_A_Single_Line()
         {
             var target = new WrapPanel()
-                         {
+            {
-                            Width = 200,
+                Width = 200,
-                            Children =
+                Children =
                             {
                                 new Border { Height = 50, Width = 100 },
                                 new Border { Height = 50, Width = 100 },
                             }
-                         };
+            };
 
             target.Measure(Size.Infinity);
             target.Arrange(new Rect(target.DesiredSize));
@@ -54,15 +54,15 @@ namespace Avalonia.Controls.UnitTests
         public void Lays_Out_Vertically_Children_On_A_Single_Line()
         {
             var target = new WrapPanel()
-                         {
+            {
-                            Orientation = Orientation.Vertical,
+                Orientation = Orientation.Vertical,
-                            Height = 120,
+                Height = 120,
-                            Children =
+                Children =
                             {
                                 new Border { Height = 50, Width = 100 },
                                 new Border { Height = 50, Width = 100 },
                             }
-                         };
+            };
 
             target.Measure(Size.Infinity);
             target.Arrange(new Rect(target.DesiredSize));
@@ -76,15 +76,15 @@ namespace Avalonia.Controls.UnitTests
         public void Lays_Out_Vertically_On_Separate_Lines()
         {
             var target = new WrapPanel()
-                         {
+            {
-                            Orientation = Orientation.Vertical,
+                Orientation = Orientation.Vertical,
-                            Height = 60,
+                Height = 60,
-                            Children =
+                Children =
                             {
                                 new Border { Height = 50, Width = 100 },
                                 new Border { Height = 50, Width = 100 },
                             }
-                         };
+            };
 
             target.Measure(Size.Infinity);
             target.Arrange(new Rect(target.DesiredSize));
@@ -98,17 +98,17 @@ namespace Avalonia.Controls.UnitTests
         public void Applies_ItemWidth_And_ItemHeight_Properties()
         {
             var target = new WrapPanel()
-                        {
+            {
-                            Orientation = Orientation.Horizontal,
+                Orientation = Orientation.Horizontal,
-                            Width = 50,
+                Width = 50,
-                            ItemWidth = 20,
+                ItemWidth = 20,
-                            ItemHeight = 15,
+                ItemHeight = 15,
-                            Children =
+                Children =
                             {
                                 new Border(),
                                 new Border(),
                             }
-                        };
+            };
 
             target.Measure(Size.Infinity);
             target.Arrange(new Rect(target.DesiredSize));
@@ -117,5 +117,33 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(new Rect(0, 0, 20, 15), target.Children[0].Bounds);
             Assert.Equal(new Rect(20, 0, 20, 15), target.Children[1].Bounds);
         }
+
+        [Fact]
+        void ItemWidth_Trigger_InvalidateMeasure()
+        {
+            var target = new WrapPanel();
+
+            target.Measure(new Size(10, 10));
+
+            Assert.True(target.IsMeasureValid);
+
+            target.ItemWidth = 1;
+
+            Assert.False(target.IsMeasureValid);
+        }
+
+        [Fact]
+        void ItemHeight_Trigger_InvalidateMeasure()
+        {
+            var target = new WrapPanel();
+
+            target.Measure(new Size(10, 10));
+
+            Assert.True(target.IsMeasureValid);
+
+            target.ItemHeight = 1;
+
+            Assert.False(target.IsMeasureValid);
+        }
     }
 }

tests/Avalonia.Input.UnitTests/PointerTests.cs

@@ -0,0 +1,39 @@
+using System.Collections.Generic;
+using System.Linq;
+using Avalonia.Controls;
+using Avalonia.UnitTests;
+using Avalonia.VisualTree;
+using Xunit;
+
+namespace Avalonia.Input.UnitTests
+{
+    public class PointerTests
+    {
+        [Fact]
+        public void On_Capture_Transfer_PointerCaptureLost_Should_Propagate_Up_To_The_Common_Parent()
+        {
+            Border initialParent, initialCapture, newParent, newCapture;
+            var el = new StackPanel
+            {
+                Children =
+                {
+                    (initialParent = new Border { Child = initialCapture = new Border() }),
+                    (newParent = new Border { Child = newCapture = new Border() })
+                }
+            };
+            var receivers = new List<object>();
+            var root = new TestRoot(el);
+            foreach (InputElement d in root.GetSelfAndVisualDescendants())
+                d.PointerCaptureLost += (s, e) => receivers.Add(s);
+            var pointer = new Pointer(Pointer.GetNextFreeId(), PointerType.Mouse, true);
+            
+            pointer.Capture(initialCapture);
+            pointer.Capture(newCapture);
+            Assert.True(receivers.SequenceEqual(new[] { initialCapture, initialParent }));
+            
+            receivers.Clear();
+            pointer.Capture(null);
+            Assert.True(receivers.SequenceEqual(new object[] { newCapture, newParent, el, root }));
+        }
+    }
+}

tests/Avalonia.ReactiveUI.UnitTests/AutoSuspendHelperTest.cs

@@ -45,7 +45,7 @@ namespace Avalonia.ReactiveUI.UnitTests
         public void AutoSuspendHelper_Should_Immediately_Fire_IsLaunchingNew() 
         {
             using (UnitTestApplication.Start(TestServices.MockWindowingPlatform)) 
-            using (var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            using (var lifetime = new ClassicDesktopStyleApplicationLifetime())
             {
                 var isLaunchingReceived = false;
                 var application = AvaloniaLocator.Current.GetService<Application>();
@@ -86,7 +86,7 @@ namespace Avalonia.ReactiveUI.UnitTests
         public void ShouldPersistState_Should_Fire_On_App_Exit_When_SuspensionDriver_Is_Initialized() 
         {
             using (UnitTestApplication.Start(TestServices.MockWindowingPlatform))
-            using (var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current)) 
+            using (var lifetime = new ClassicDesktopStyleApplicationLifetime()) 
             {
                 var shouldPersistReceived = false;
                 var application = AvaloniaLocator.Current.GetService<Application>();
@@ -105,4 +105,4 @@ namespace Avalonia.ReactiveUI.UnitTests
             }
         }
     }
-}
+}

tests/Avalonia.UnitTests/MouseTestHelper.cs

@@ -84,9 +84,9 @@ namespace Avalonia.UnitTests
             );
             if (ButtonCount(props) == 0)
             {
-                _pointer.Capture(null);
                 target.RaiseEvent(new PointerReleasedEventArgs(source, _pointer, (IVisual)target, position,
                     Timestamp(), props, GetModifiers(modifiers), _pressedButton));
+                _pointer.Capture(null);
             }
             else
                 Move(target, source, position);

tests/Avalonia.UnitTests/TestRoot.cs

@@ -24,8 +24,19 @@ namespace Avalonia.UnitTests
         }
 
         public TestRoot(IControl child)
+            : this(false, child)
+        {
+            Child = child;
+        }
+
+        public TestRoot(bool useGlobalStyles, IControl child)
             : this()
         {
+            if (useGlobalStyles)
+            {
+                StylingParent = UnitTestApplication.Current;
+            }
+
             Child = child;
         }
 

tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs

@@ -369,6 +369,81 @@ namespace Avalonia.Visuals.UnitTests.Rendering
 
         }
 
+        [Fact]
+        public void Should_Update_VisualNodes_When_Child_Moved_To_New_Parent_And_New_Root()
+        {
+            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(),
+                        })
+                    }
+                }
+            };
+
+            var otherRoot = new TestRoot
+            {
+                Child = new StackPanel
+                {
+                    Children =
+                    {
+                        (moveTo = new Decorator())
+                    }
+                }
+            };
+
+            var sceneBuilder = new SceneBuilder();
+            var target = new DeferredRenderer(
+                root,
+                loop.Object,
+                sceneBuilder: sceneBuilder,
+                dispatcher: dispatcher);
+
+            var otherSceneBuilder = new SceneBuilder();
+            var otherTarget = new DeferredRenderer(
+                otherRoot,
+                loop.Object,
+                sceneBuilder: otherSceneBuilder,
+                dispatcher: dispatcher);
+
+            root.Renderer = target;
+            otherRoot.Renderer = otherTarget;
+
+            target.Start();
+            otherTarget.Start();
+
+            RunFrame(target);
+            RunFrame(otherTarget);
+
+            moveFrom.Child = null;
+            moveTo.Child = moveMe;
+
+            RunFrame(target);
+            RunFrame(otherTarget);
+
+            var scene = target.UnitTestScene();
+            var otherScene = otherTarget.UnitTestScene();
+
+            var moveFromNode = (VisualNode)scene.FindNode(moveFrom);
+            var moveToNode = (VisualNode)otherScene.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()
         {