diff --git a/native/Avalonia.Native/src/OSX/window.mm b/native/Avalonia.Native/src/OSX/window.mm
index 14fe60ab0b..7a6e7dc72f 100644
--- a/native/Avalonia.Native/src/OSX/window.mm
+++ b/native/Avalonia.Native/src/OSX/window.mm
@@ -641,6 +641,7 @@ private:
         [Window setCanBecomeKeyAndMain];
         [Window disableCursorRects];
         [Window setTabbingMode:NSWindowTabbingModeDisallowed];
+        [Window setCollectionBehavior:NSWindowCollectionBehaviorFullScreenPrimary];
     }
     
     void HideOrShowTrafficLights ()
@@ -1091,14 +1092,7 @@ private:
     {
         _fullScreenActive = true;
         
-        [Window setHasShadow:YES];
-        [Window setTitleVisibility:NSWindowTitleVisible];
-        [Window setTitlebarAppearsTransparent:NO];
         [Window setTitle:_lastTitle];
-        
-        Window.styleMask = Window.styleMask | NSWindowStyleMaskTitled | NSWindowStyleMaskResizable;
-        Window.styleMask = Window.styleMask & ~NSWindowStyleMaskFullSizeContentView;
-    
         [Window toggleFullScreen:nullptr];
     }
     
@@ -1672,6 +1666,7 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
 
     switch(event.buttonNumber)
     {
+        case 2:
         case 3:
             _isMiddlePressed = true;
             [self mouseEvent:event withType:MiddleButtonDown];
@@ -1704,6 +1699,7 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
 {
     switch(event.buttonNumber)
     {
+        case 2:
         case 3:
             _isMiddlePressed = false;
             [self mouseEvent:event withType:MiddleButtonUp];
diff --git a/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs b/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs
index 9ec600d2bc..2385d4981c 100644
--- a/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs
+++ b/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs
@@ -26,7 +26,7 @@ namespace Avalonia.Data.Converters
         /// <inheritdoc/>
         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
-            if (value is TIn || (value == null && TypeUtilities.AcceptsNull(typeof(TIn))))
+            if (TypeUtilities.CanCast<TIn>(value))
             {
                 return _convert((TIn)value);
             }
diff --git a/src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs b/src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs
index 1a78792173..326d1a3f53 100644
--- a/src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs
+++ b/src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs
@@ -39,7 +39,7 @@ namespace Avalonia.Threading
             if (Dispatcher.UIThread.CheckAccess())
                 d(state);
             else
-                Dispatcher.UIThread.InvokeAsync(() => d(state), DispatcherPriority.Send).Wait();
+                Dispatcher.UIThread.InvokeAsync(() => d(state), DispatcherPriority.Send).GetAwaiter().GetResult();
         }
 
 
diff --git a/src/Avalonia.Base/Utilities/TypeUtilities.cs b/src/Avalonia.Base/Utilities/TypeUtilities.cs
index 179ded3549..0978308ef6 100644
--- a/src/Avalonia.Base/Utilities/TypeUtilities.cs
+++ b/src/Avalonia.Base/Utilities/TypeUtilities.cs
@@ -3,6 +3,7 @@ using System.ComponentModel;
 using System.Globalization;
 using System.Linq;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 
 namespace Avalonia.Utilities
 {
@@ -93,6 +94,17 @@ namespace Avalonia.Utilities
             return !type.IsValueType || IsNullableType(type);
         }
 
+        /// <summary>
+        /// Returns a value indicating whether null can be assigned to the specified type.
+        /// </summary>
+        /// <typeparam name="T">The type</typeparam>
+        /// <returns>True if the type accepts null values; otherwise false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool AcceptsNull<T>()
+        {
+            return default(T) is null;
+        }
+
         /// <summary>
         /// Returns a value indicating whether value can be casted to the specified type.
         /// If value is null, checks if instances of that type can be null.
@@ -102,7 +114,7 @@ namespace Avalonia.Utilities
         /// <returns>True if the cast is possible, otherwise false.</returns>
         public static bool CanCast<T>(object value)
         {
-            return value is T || (value is null && AcceptsNull(typeof(T)));
+            return value is T || (value is null && AcceptsNull<T>());
         }
 
         /// <summary>
diff --git a/src/Avalonia.Controls/AutoCompleteBox.cs b/src/Avalonia.Controls/AutoCompleteBox.cs
index 5a6e78f441..0e946126ea 100644
--- a/src/Avalonia.Controls/AutoCompleteBox.cs
+++ b/src/Avalonia.Controls/AutoCompleteBox.cs
@@ -2094,7 +2094,21 @@ namespace Avalonia.Controls
                 bool inResults = !(stringFiltering || objectFiltering);
                 if (!inResults)
                 {
-                    inResults = stringFiltering ? TextFilter(text, FormatValue(item)) : ItemFilter(text, item);
+                    if (stringFiltering)
+                    {
+                        inResults = TextFilter(text, FormatValue(item));
+                    }
+                    else
+                    {
+                        if (ItemFilter is null)
+                        {
+                            throw new Exception("ItemFilter property can not be null when FilterMode has value AutoCompleteFilterMode.Custom");
+                        }
+                        else
+                        {
+                            inResults = ItemFilter(text, item);
+                        }
+                    }
                 }
 
                 if (view_count > view_index && inResults && _view[view_index] == item)
diff --git a/src/Avalonia.Controls/TextBox.cs b/src/Avalonia.Controls/TextBox.cs
index 0eade8d6df..9eae928eeb 100644
--- a/src/Avalonia.Controls/TextBox.cs
+++ b/src/Avalonia.Controls/TextBox.cs
@@ -145,6 +145,18 @@ namespace Avalonia.Controls
                 (o, v) => o.UndoLimit = v,
                 unsetValue: -1);
 
+        public static readonly RoutedEvent<RoutedEventArgs> CopyingToClipboardEvent =
+            RoutedEvent.Register<TextBox, RoutedEventArgs>(
+                "CopyingToClipboard", RoutingStrategies.Bubble);
+
+        public static readonly RoutedEvent<RoutedEventArgs> CuttingToClipboardEvent =
+            RoutedEvent.Register<TextBox, RoutedEventArgs>(
+                "CuttingToClipboard", RoutingStrategies.Bubble);
+
+        public static readonly RoutedEvent<RoutedEventArgs> PastingFromClipboardEvent =
+            RoutedEvent.Register<TextBox, RoutedEventArgs>(
+                "PastingFromClipboard", RoutingStrategies.Bubble);
+
         readonly struct UndoRedoState : IEquatable<UndoRedoState>
         {
             public string Text { get; }
@@ -500,6 +512,24 @@ namespace Avalonia.Controls
             }
         }
 
+        public event EventHandler<RoutedEventArgs> CopyingToClipboard
+        {
+            add => AddHandler(CopyingToClipboardEvent, value);
+            remove => RemoveHandler(CopyingToClipboardEvent, value);
+        }
+
+        public event EventHandler<RoutedEventArgs> CuttingToClipboard
+        {
+            add => AddHandler(CuttingToClipboardEvent, value);
+            remove => RemoveHandler(CuttingToClipboardEvent, value);
+        }
+
+        public event EventHandler<RoutedEventArgs> PastingFromClipboard
+        {
+            add => AddHandler(PastingFromClipboardEvent, value);
+            remove => RemoveHandler(PastingFromClipboardEvent, value);
+        }
+
         protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
         {
             _presenter = e.NameScope.Get<TextPresenter>("PART_TextPresenter");
@@ -638,27 +668,54 @@ namespace Avalonia.Controls
         public async void Cut()
         {
             var text = GetSelection();
-            if (text is null) return;
+            if (string.IsNullOrEmpty(text))
+            {
+                return;
+            }
 
-            SnapshotUndoRedo();
-            Copy();
-            DeleteSelection();
+            var eventArgs = new RoutedEventArgs(CuttingToClipboardEvent);
+            RaiseEvent(eventArgs);
+            if (!eventArgs.Handled)
+            {
+                SnapshotUndoRedo();
+                await ((IClipboard)AvaloniaLocator.Current.GetService(typeof(IClipboard)))
+                    .SetTextAsync(text);
+                DeleteSelection();
+            }
         }
 
         public async void Copy()
         {
             var text = GetSelection();
-            if (text is null) return;
+            if (string.IsNullOrEmpty(text))
+            {
+                return;
+            }
 
-            await ((IClipboard)AvaloniaLocator.Current.GetService(typeof(IClipboard)))
-                .SetTextAsync(text);
+            var eventArgs = new RoutedEventArgs(CopyingToClipboardEvent);
+            RaiseEvent(eventArgs);
+            if (!eventArgs.Handled)
+            {
+                await ((IClipboard)AvaloniaLocator.Current.GetService(typeof(IClipboard)))
+                    .SetTextAsync(text);
+            }
         }
 
         public async void Paste()
         {
+            var eventArgs = new RoutedEventArgs(PastingFromClipboardEvent);
+            RaiseEvent(eventArgs);
+            if (eventArgs.Handled)
+            {
+                return;
+            }
+
             var text = await ((IClipboard)AvaloniaLocator.Current.GetService(typeof(IClipboard))).GetTextAsync();
 
-            if (text is null) return;
+            if (string.IsNullOrEmpty(text))
+            {
+                return;
+            }
 
             SnapshotUndoRedo();
             HandleTextInput(text);
diff --git a/src/Avalonia.Input/AccessKeyHandler.cs b/src/Avalonia.Input/AccessKeyHandler.cs
index 5c4af68d79..5082265ea6 100644
--- a/src/Avalonia.Input/AccessKeyHandler.cs
+++ b/src/Avalonia.Input/AccessKeyHandler.cs
@@ -157,10 +157,9 @@ namespace Avalonia.Input
 
                     _restoreFocusElement?.Focus();
                     _restoreFocusElement = null;
+                    
+                    e.Handled = true;
                 }
-
-                // We always handle the Alt key.
-                e.Handled = true;
             }
             else if (_altIsDown)
             {
diff --git a/src/Markup/Avalonia.Markup.Xaml.Loader/xamlil.github b/src/Markup/Avalonia.Markup.Xaml.Loader/xamlil.github
index 9e90d34e97..f4ac681b91 160000
--- a/src/Markup/Avalonia.Markup.Xaml.Loader/xamlil.github
+++ b/src/Markup/Avalonia.Markup.Xaml.Loader/xamlil.github
@@ -1 +1 @@
-Subproject commit 9e90d34e97c766ba8dcb70128147fcded65d195a
+Subproject commit f4ac681b91a9dc7a7a095d1050a683de23d86b72
diff --git a/src/Windows/Avalonia.Win32/WindowImpl.cs b/src/Windows/Avalonia.Win32/WindowImpl.cs
index 3b7d3efa2f..8fc25f8cfa 100644
--- a/src/Windows/Avalonia.Win32/WindowImpl.cs
+++ b/src/Windows/Avalonia.Win32/WindowImpl.cs
@@ -263,10 +263,8 @@ namespace Avalonia.Win32
                 {
                     ShowWindow(value, true);
                 }
-                else
-                {
-                    _showWindowState = value;
-                }
+
+                _showWindowState = value;                
             }
         }
 
diff --git a/tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs b/tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs
index b346fca330..c8bd289e54 100644
--- a/tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs
@@ -105,6 +105,16 @@ namespace Avalonia.Controls.UnitTests
             });
         }
 
+        [Fact]
+        public void Custom_FilterMode_Without_ItemFilter_Setting_Throws_Exception()
+        {
+            RunTest((control, textbox) =>
+            {
+                control.FilterMode = AutoCompleteFilterMode.Custom;
+                Assert.Throws<Exception>(() => { control.Text = "a"; });
+            });
+        }
+
         [Fact]
         public void Text_Completion_Via_Text_Property()
         {