Merge branch 'master' into fixes/menu-grid-sharedsizescope

samples/ControlCatalog/Pages/ListBoxPage.xaml

@@ -11,8 +11,7 @@
               Spacing="16">
       <StackPanel Orientation="Vertical" Spacing="8">
         <ListBox Items="{Binding Items}"
-                 SelectedItem="{Binding SelectedItem}"
-                 SelectedItems="{Binding SelectedItems}"
+                 Selection="{Binding Selection}"
                  AutoScrollToSelectedItem="True"
                  SelectionMode="{Binding SelectionMode}"
                  Width="250"

samples/ControlCatalog/Pages/ListBoxPage.xaml.cs

@@ -1,10 +1,6 @@
-using System;
-using System.Collections.ObjectModel;
-using System.Linq;
-using System.Reactive;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
-using ReactiveUI;
+using ControlCatalog.ViewModels;
 
 namespace ControlCatalog.Pages
 {
@@ -13,72 +9,12 @@ namespace ControlCatalog.Pages
         public ListBoxPage()
         {
             InitializeComponent();
-            DataContext = new PageViewModel();
+            DataContext = new ListBoxPageViewModel();
         }
 
         private void InitializeComponent()
         {
             AvaloniaXamlLoader.Load(this);
         }
-
-        private class PageViewModel : ReactiveObject
-        {
-            private int _counter;
-            private SelectionMode _selectionMode;
-
-            public PageViewModel()
-            {
-                Items = new ObservableCollection<string>(Enumerable.Range(1, 10000).Select(i => GenerateItem()));
-                SelectedItems = new ObservableCollection<string>();
-
-                AddItemCommand = ReactiveCommand.Create(() => Items.Add(GenerateItem()));
-
-                RemoveItemCommand = ReactiveCommand.Create(() =>
-                {
-                    while (SelectedItems.Count > 0)
-                    {
-                        Items.Remove(SelectedItems[0]);
-                    }
-                });
-
-                SelectRandomItemCommand = ReactiveCommand.Create(() =>
-                {
-                    var random = new Random();
-
-                    SelectedItem = Items[random.Next(Items.Count - 1)];
-                });
-            }
-
-            public ObservableCollection<string> Items { get; }
-
-            private string _selectedItem;
-
-            public string SelectedItem
-            {
-                get { return _selectedItem; }
-                set { this.RaiseAndSetIfChanged(ref _selectedItem, value); }
-            }
-
-
-            public ObservableCollection<string> SelectedItems { get; }
-
-            public ReactiveCommand<Unit, Unit> AddItemCommand { get; }
-
-            public ReactiveCommand<Unit, Unit> RemoveItemCommand { get; }
-
-            public ReactiveCommand<Unit, Unit> SelectRandomItemCommand { get; }
-
-            public SelectionMode SelectionMode
-            {
-                get => _selectionMode;
-                set
-                {
-                    SelectedItems.Clear();
-                    this.RaiseAndSetIfChanged(ref _selectionMode, value);
-                }
-            }
-
-            private string GenerateItem() => $"Item {_counter++.ToString()}";
-        }
     }
 }

samples/ControlCatalog/ViewModels/ListBoxPageViewModel.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Reactive;
+using Avalonia.Controls;
+using ReactiveUI;
+
+namespace ControlCatalog.ViewModels
+{
+    public class ListBoxPageViewModel : ReactiveObject
+    {
+        private int _counter;
+        private SelectionMode _selectionMode;
+
+        public ListBoxPageViewModel()
+        {
+            Items = new ObservableCollection<string>(Enumerable.Range(1, 10000).Select(i => GenerateItem()));
+            Selection = new SelectionModel();
+            Selection.Select(1);
+
+            AddItemCommand = ReactiveCommand.Create(() => Items.Add(GenerateItem()));
+
+            RemoveItemCommand = ReactiveCommand.Create(() =>
+            {
+                while (Selection.SelectedItems.Count > 0)
+                {
+                    Items.Remove((string)Selection.SelectedItems.First());
+                }
+            });
+
+            SelectRandomItemCommand = ReactiveCommand.Create(() =>
+            {
+                var random = new Random();
+
+                using (Selection.Update())
+                {
+                    Selection.ClearSelection();
+                    Selection.Select(random.Next(Items.Count - 1));
+                }
+            });
+        }
+
+        public ObservableCollection<string> Items { get; }
+
+        public SelectionModel Selection { get; }
+
+        public ReactiveCommand<Unit, Unit> AddItemCommand { get; }
+
+        public ReactiveCommand<Unit, Unit> RemoveItemCommand { get; }
+
+        public ReactiveCommand<Unit, Unit> SelectRandomItemCommand { get; }
+
+        public SelectionMode SelectionMode
+        {
+            get => _selectionMode;
+            set
+            {
+                Selection.ClearSelection();
+                this.RaiseAndSetIfChanged(ref _selectionMode, value);
+            }
+        }
+
+        private string GenerateItem() => $"Item {_counter++.ToString()}";
+    }
+}

src/Avalonia.Controls/ApiCompatBaseline.txt

@@ -0,0 +1,7 @@
+Compat issues with assembly Avalonia.Controls:
+MembersMustExist : Member 'protected void Avalonia.Controls.ComboBox.PopupClosedOverride(Avalonia.Controls.Primitives.PopupClosedEventArgs)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public Avalonia.StyledProperty<System.Boolean> Avalonia.StyledProperty<System.Boolean> Avalonia.Controls.Primitives.Popup.StaysOpenProperty' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.Primitives.Popup.add_Closed(System.EventHandler<Avalonia.Controls.Primitives.PopupClosedEventArgs>)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.Primitives.Popup.remove_Closed(System.EventHandler<Avalonia.Controls.Primitives.PopupClosedEventArgs>)' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'Avalonia.Controls.Primitives.PopupClosedEventArgs' does not exist in the implementation but it does exist in the contract.
+Total Issues: 5

src/Avalonia.Controls/AutoCompleteBox.cs

@@ -1647,7 +1647,7 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="sender">The source object.</param>
         /// <param name="e">The event data.</param>
-        private void DropDownPopup_Closed(object sender, PopupClosedEventArgs e)
+        private void DropDownPopup_Closed(object sender, EventArgs e)
         {
             // Force the drop down dependency property to be false.
             if (IsDropDownOpen)
@@ -1655,11 +1655,6 @@ namespace Avalonia.Controls
                 IsDropDownOpen = false;
             }
 
-            if (e.CloseEvent is PointerEventArgs pointerEvent)
-            {
-                pointerEvent.Handled = true;
-            }
-
             // Fire the DropDownClosed event
             if (_popupHasOpened)
             {

src/Avalonia.Controls/Calendar/CalendarDatePicker.cs

@@ -889,17 +889,12 @@ namespace Avalonia.Controls
                 _ignoreButtonClick = false;
             }
         }
-        private void PopUp_Closed(object sender, PopupClosedEventArgs e)
+        private void PopUp_Closed(object sender, EventArgs e)
         {
             IsDropDownOpen = false;
 
             if(!_isPopupClosing)
             {
-                if (e.CloseEvent is PointerEventArgs pointerEvent)
-                {
-                    pointerEvent.Handled = true;
-                }
-
                 _isPopupClosing = true;
                 Threading.Dispatcher.UIThread.InvokeAsync(() => _isPopupClosing = false);
             }

src/Avalonia.Controls/ComboBox.cs

@@ -290,24 +290,6 @@ namespace Avalonia.Controls
 
             _popup = e.NameScope.Get<Popup>("PART_Popup");
             _popup.Opened += PopupOpened;
-            _popup.Closed += PopupClosed;
-        }
-
-        /// <summary>
-        /// Called when the ComboBox popup is closed, with the <see cref="PopupClosedEventArgs"/>
-        /// that caused the popup to close.
-        /// </summary>
-        /// <param name="e">The event args.</param>
-        /// <remarks>
-        /// This method can be overridden to control whether the event that caused the popup to close
-        /// is swallowed or passed through.
-        /// </remarks>
-        protected virtual void PopupClosedOverride(PopupClosedEventArgs e)
-        {
-            if (e.CloseEvent is PointerEventArgs pointerEvent)
-            {
-                pointerEvent.Handled = true;
-            }
         }
 
         internal void ItemFocused(ComboBoxItem dropDownItem)
@@ -318,13 +300,11 @@ namespace Avalonia.Controls
             }
         }
 
-        private void PopupClosed(object sender, PopupClosedEventArgs e)
+        private void PopupClosed(object sender, EventArgs e)
         {
             _subscriptionsOnOpen?.Dispose();
             _subscriptionsOnOpen = null;
 
-            PopupClosedOverride(e);
-
             if (CanFocus(this))
             {
                 Focus();

src/Avalonia.Controls/ContextMenu.cs

@@ -265,7 +265,8 @@ namespace Avalonia.Controls
                     PlacementMode = PlacementMode,
                     PlacementRect = PlacementRect,
                     PlacementTarget = PlacementTarget ?? control,
-                    StaysOpen = false
+                    IsLightDismissEnabled = true,
+                    OverlayDismissEventPassThrough = true,
                 };
 
                 _popup.Opened += PopupOpened;

src/Avalonia.Controls/IMenuElement.cs

@@ -1,6 +1,8 @@
 using System.Collections.Generic;
 using Avalonia.Input;
 
+#nullable enable
+
 namespace Avalonia.Controls
 {
     /// <summary>
@@ -11,7 +13,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets the currently selected submenu item.
         /// </summary>
-        IMenuItem SelectedItem { get; set; }
+        IMenuItem? SelectedItem { get; set; }
 
         /// <summary>
         /// Gets the submenu items.

src/Avalonia.Controls/IMenuItem.cs

@@ -1,4 +1,6 @@
-namespace Avalonia.Controls
+#nullable enable
+
+namespace Avalonia.Controls
 {
     /// <summary>
     /// Represents a <see cref="MenuItem"/>.
@@ -29,7 +31,7 @@
         /// <summary>
         /// Gets the parent <see cref="IMenuElement"/>.
         /// </summary>
-        new IMenuElement Parent { get; }
+        new IMenuElement? Parent { get; }
 
         /// <summary>
         /// Raises a click event on the menu item.

src/Avalonia.Controls/ItemsControl.cs

@@ -295,7 +295,7 @@ namespace Avalonia.Controls
 
                         if (next != null)
                         {
-                            focus.Focus(next, NavigationMethod.Directional);
+                            focus.Focus(next, NavigationMethod.Directional, e.KeyModifiers);
                             e.Handled = true;
                         }
 

src/Avalonia.Controls/ListBox.cs

@@ -136,7 +136,8 @@ namespace Avalonia.Controls
                 e.Handled = UpdateSelectionFromEventSource(
                     e.Source,
                     true,
-                    (e.KeyModifiers & KeyModifiers.Shift) != 0);
+                    (e.KeyModifiers & KeyModifiers.Shift) != 0,
+                    (e.KeyModifiers & KeyModifiers.Control) != 0);
             }
         }
 

src/Avalonia.Controls/Menu.cs

@@ -1,9 +1,12 @@
 using Avalonia.Controls.Platform;
+using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Layout;
 
+#nullable enable
+
 namespace Avalonia.Controls
 {
     /// <summary>
@@ -14,6 +17,8 @@ namespace Avalonia.Controls
         private static readonly ITemplate<IPanel> DefaultPanel =
             new FuncTemplate<IPanel>(() => new StackPanel { Orientation = Orientation.Horizontal });
 
+        private LightDismissOverlayLayer? _overlay;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="Menu"/> class.
         /// </summary>

src/Avalonia.Controls/MenuBase.cs

@@ -8,6 +8,8 @@ using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.LogicalTree;
 
+#nullable enable
+
 namespace Avalonia.Controls
 {
     /// <summary>
@@ -51,9 +53,7 @@ namespace Avalonia.Controls
         /// <param name="interactionHandler">The menu interaction handler.</param>
         public MenuBase(IMenuInteractionHandler interactionHandler)
         {
-            Contract.Requires<ArgumentNullException>(interactionHandler != null);
-
-            InteractionHandler = interactionHandler;
+            InteractionHandler = interactionHandler ?? throw new ArgumentNullException(nameof(interactionHandler));
         }
 
         /// <summary>
@@ -77,7 +77,7 @@ namespace Avalonia.Controls
         IMenuInteractionHandler IMenu.InteractionHandler => InteractionHandler;
 
         /// <inheritdoc/>
-        IMenuItem IMenuElement.SelectedItem
+        IMenuItem? IMenuElement.SelectedItem
         {
             get
             {

src/Avalonia.Controls/MenuItem.cs

@@ -13,6 +13,8 @@ using Avalonia.Interactivity;
 using Avalonia.LogicalTree;
 using Avalonia.VisualTree;
 
+#nullable enable
+
 namespace Avalonia.Controls
 {
     /// <summary>
@@ -23,7 +25,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Defines the <see cref="Command"/> property.
         /// </summary>
-        public static readonly DirectProperty<MenuItem, ICommand> CommandProperty =
+        public static readonly DirectProperty<MenuItem, ICommand?> CommandProperty =
             Button.CommandProperty.AddOwner<MenuItem>(
                 menuItem => menuItem.Command,
                 (menuItem, command) => menuItem.Command = command,
@@ -95,7 +97,7 @@ namespace Avalonia.Controls
         private static readonly ITemplate<IPanel> DefaultPanel =
             new FuncTemplate<IPanel>(() => new StackPanel());
 
-        private ICommand _command;
+        private ICommand? _command;
         private bool _commandCanExecute = true;
         private Popup _popup;
 
@@ -192,7 +194,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets the command associated with the menu item.
         /// </summary>
-        public ICommand Command
+        public ICommand? Command
         {
             get { return _command; }
             set { SetAndRaise(CommandProperty, ref _command, value); }
@@ -272,7 +274,7 @@ namespace Avalonia.Controls
         bool IMenuItem.IsPointerOverSubMenu => _popup?.IsPointerOverPopup ?? false; 
 
         /// <inheritdoc/>
-        IMenuElement IMenuItem.Parent => Parent as IMenuElement;
+        IMenuElement? IMenuItem.Parent => Parent as IMenuElement;
 
         protected override bool IsEnabledCore => base.IsEnabledCore && _commandCanExecute;
 
@@ -280,7 +282,7 @@ namespace Avalonia.Controls
         bool IMenuElement.MoveSelection(NavigationDirection direction, bool wrap) => MoveSelection(direction, wrap);
 
         /// <inheritdoc/>
-        IMenuItem IMenuElement.SelectedItem
+        IMenuItem? IMenuElement.SelectedItem
         {
             get
             {
@@ -551,7 +553,7 @@ namespace Avalonia.Controls
         /// <param name="e">The property change event.</param>
         private void IsSelectedChanged(AvaloniaPropertyChangedEventArgs e)
         {
-            if ((bool)e.NewValue)
+            if ((bool)e.NewValue!)
             {
                 Focus();
             }
@@ -563,7 +565,7 @@ namespace Avalonia.Controls
         /// <param name="e">The property change event.</param>
         private void SubMenuOpenChanged(AvaloniaPropertyChangedEventArgs e)
         {
-            var value = (bool)e.NewValue;
+            var value = (bool)e.NewValue!;
 
             if (value)
             {

src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs

@@ -3,7 +3,6 @@ using Avalonia.Input;
 using Avalonia.Input.Raw;
 using Avalonia.Interactivity;
 using Avalonia.LogicalTree;
-using Avalonia.Platform;
 using Avalonia.Rendering;
 using Avalonia.Threading;
 using Avalonia.VisualTree;
@@ -235,7 +234,9 @@ namespace Avalonia.Controls.Platform
                             // If the the parent is an IMenu which successfully moved its selection,
                             // and the current menu is open then close the current menu and open the
                             // new menu.
-                            if (item.IsSubMenuOpen && item.Parent is IMenu)
+                            if (item.IsSubMenuOpen &&
+                                item.Parent is IMenu &&
+                                item.Parent.SelectedItem is object)
                             {
                                 item.Close();
                                 Open(item.Parent.SelectedItem, true);
@@ -363,6 +364,11 @@ namespace Avalonia.Controls.Platform
                 }
                 else
                 {
+                    if (item.IsTopLevel && item.Parent is IMainMenu mainMenu)
+                    {
+                        mainMenu.Open();
+                    }
+
                     Open(item, false);
                 }
 
@@ -385,7 +391,7 @@ namespace Avalonia.Controls.Platform
         {
             if (e.Source == Menu)
             {
-                Menu.MoveSelection(NavigationDirection.First, true);
+                Menu?.MoveSelection(NavigationDirection.First, true);
             }
         }
 

src/Avalonia.Controls/Primitives/LightDismissOverlayLayer.cs

@@ -0,0 +1,61 @@
+using System;
+using System.Linq;
+using Avalonia.Controls.Templates;
+using Avalonia.Input;
+using Avalonia.Rendering;
+using Avalonia.Styling;
+using Avalonia.VisualTree;
+
+#nullable enable
+
+namespace Avalonia.Controls.Primitives
+{
+    /// <summary>
+    /// A layer that is used to dismiss a <see cref="Popup"/> when the user clicks outside.
+    /// </summary>
+    public class LightDismissOverlayLayer : Border, ICustomHitTest
+    {
+        public IInputElement? InputPassThroughElement { get; set; }
+
+        /// <summary>
+        /// Returns the light dismiss overlay for a specified visual.
+        /// </summary>
+        /// <param name="visual">The visual.</param>
+        /// <returns>The light dismiss overlay, or null if none found.</returns>
+        public static LightDismissOverlayLayer? GetLightDismissOverlayLayer(IVisual visual)
+        {
+            visual = visual ?? throw new ArgumentNullException(nameof(visual));
+
+            VisualLayerManager? manager;
+
+            if (visual is TopLevel topLevel)
+            {
+                manager = topLevel.GetTemplateChildren()
+                    .OfType<VisualLayerManager>()
+                    .FirstOrDefault();
+            }
+            else
+            {
+                manager = visual.FindAncestorOfType<VisualLayerManager>();
+            }
+
+            return manager?.LightDismissOverlayLayer;
+        }
+
+        public bool HitTest(Point point)
+        {
+            if (InputPassThroughElement is object)
+            {
+                var p = point.Transform(this.TransformToVisual(VisualRoot)!.Value);
+                var hit = VisualRoot.GetVisualAt(p, x => x != this);
+
+                if (hit is object)
+                {
+                    return !InputPassThroughElement.IsVisualAncestorOf(hit);
+                }
+            }
+
+            return true;
+        }
+    }
+}

src/Avalonia.Controls/Primitives/Popup.cs

@@ -1,12 +1,10 @@
 using System;
-using System.Diagnostics;
 using System.Linq;
 using System.Reactive.Disposables;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives.PopupPositioning;
 using Avalonia.Input;
 using Avalonia.Input.Raw;
-using Avalonia.Interactivity;
 using Avalonia.LogicalTree;
 using Avalonia.Metadata;
 using Avalonia.Platform;
@@ -86,12 +84,27 @@ namespace Avalonia.Controls.Primitives
             AvaloniaProperty.Register<Popup, bool>(nameof(ObeyScreenEdges), true);
 #pragma warning restore 618
 
+        public static readonly StyledProperty<bool> OverlayDismissEventPassThroughProperty =
+            AvaloniaProperty.Register<Popup, bool>(nameof(OverlayDismissEventPassThrough));
+
+        public static readonly DirectProperty<Popup, IInputElement> OverlayInputPassThroughElementProperty =
+            AvaloniaProperty.RegisterDirect<Popup, IInputElement>(
+                nameof(OverlayInputPassThroughElement),
+                o => o.OverlayInputPassThroughElement,
+                (o, v) => o.OverlayInputPassThroughElement = v);
+
         /// <summary>
         /// Defines the <see cref="HorizontalOffset"/> property.
         /// </summary>
         public static readonly StyledProperty<double> HorizontalOffsetProperty =
             AvaloniaProperty.Register<Popup, double>(nameof(HorizontalOffset));
 
+        /// <summary>
+        /// Defines the <see cref="IsLightDismissEnabled"/> property.
+        /// </summary>
+        public static readonly StyledProperty<bool> IsLightDismissEnabledProperty =
+            AvaloniaProperty.Register<Popup, bool>(nameof(IsLightDismissEnabled));
+
         /// <summary>
         /// Defines the <see cref="VerticalOffset"/> property.
         /// </summary>
@@ -101,8 +114,13 @@ namespace Avalonia.Controls.Primitives
         /// <summary>
         /// Defines the <see cref="StaysOpen"/> property.
         /// </summary>
-        public static readonly StyledProperty<bool> StaysOpenProperty =
-            AvaloniaProperty.Register<Popup, bool>(nameof(StaysOpen), true);
+        [Obsolete("Use IsLightDismissEnabledProperty")]
+        public static readonly DirectProperty<Popup, bool> StaysOpenProperty =
+            AvaloniaProperty.RegisterDirect<Popup, bool>(
+                nameof(StaysOpen),
+                o => o.StaysOpen,
+                (o, v) => o.StaysOpen = v,
+                true);
 
         /// <summary>
         /// Defines the <see cref="Topmost"/> property.
@@ -113,6 +131,7 @@ namespace Avalonia.Controls.Primitives
         private bool _isOpen;
         private bool _ignoreIsOpenChanged;
         private PopupOpenState? _openState;
+        private IInputElement _overlayInputPassThroughElement;
 
         /// <summary>
         /// Initializes static members of the <see cref="Popup"/> class.
@@ -127,7 +146,7 @@ namespace Avalonia.Controls.Primitives
         /// <summary>
         /// Raised when the popup closes.
         /// </summary>
-        public event EventHandler<PopupClosedEventArgs>? Closed;
+        public event EventHandler<EventArgs>? Closed;
 
         /// <summary>
         /// Raised when the popup opens.
@@ -165,6 +184,18 @@ namespace Avalonia.Controls.Primitives
             set;
         }
 
+        /// <summary>
+        /// Gets or sets a value that determines how the <see cref="Popup"/> can be dismissed.
+        /// </summary>
+        /// <remarks>
+        /// Light dismiss is when the user taps on any area other than the popup.
+        /// </remarks>
+        public bool IsLightDismissEnabled
+        {
+            get => GetValue(IsLightDismissEnabledProperty);
+            set => SetValue(IsLightDismissEnabledProperty, value);
+        }
+
         /// <summary>
         /// Gets or sets a value indicating whether the popup is currently open.
         /// </summary>
@@ -246,6 +277,32 @@ namespace Avalonia.Controls.Primitives
             set => SetValue(ObeyScreenEdgesProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether the event that closes the popup is passed
+        /// through to the parent window.
+        /// </summary>
+        /// <remarks>
+        /// When <see cref="IsLightDismissEnabled"/> is set to true, clicks outside the the popup
+        /// cause the popup to close. When <see cref="OverlayDismissEventPassThrough"/> is set to
+        /// false, these clicks will be handled by the popup and not be registered by the parent
+        /// window. When set to true, the events will be passed through to the parent window.
+        /// </remarks>
+        public bool OverlayDismissEventPassThrough
+        {
+            get => GetValue(OverlayDismissEventPassThroughProperty);
+            set => SetValue(OverlayDismissEventPassThroughProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets an element that should receive pointer input events even when underneath
+        /// the popup's overlay.
+        /// </summary>
+        public IInputElement OverlayInputPassThroughElement
+        {
+            get => _overlayInputPassThroughElement;
+            set => SetAndRaise(OverlayInputPassThroughElementProperty, ref _overlayInputPassThroughElement, value);
+        }
+
         /// <summary>
         /// Gets or sets the Horizontal offset of the popup in relation to the <see cref="PlacementTarget"/>.
         /// </summary>
@@ -268,10 +325,11 @@ namespace Avalonia.Controls.Primitives
         /// Gets or sets a value indicating whether the popup should stay open when the popup is
         /// pressed or loses focus.
         /// </summary>
+        [Obsolete("Use IsLightDismissEnabled")]
         public bool StaysOpen
         {
-            get { return GetValue(StaysOpenProperty); }
-            set { SetValue(StaysOpenProperty, value); }
+            get => !IsLightDismissEnabled;
+            set => IsLightDismissEnabled = !value;
         }
 
         /// <summary>
@@ -363,14 +421,12 @@ namespace Avalonia.Controls.Primitives
 
                 if (parentPopupRoot?.Parent is Popup popup)
                 {
-                    DeferCleanup(SubscribeToEventHandler<Popup, EventHandler<PopupClosedEventArgs>>(popup, ParentClosed,
+                    DeferCleanup(SubscribeToEventHandler<Popup, EventHandler<EventArgs>>(popup, ParentClosed,
                         (x, handler) => x.Closed += handler,
                         (x, handler) => x.Closed -= handler));
                 }
             }
 
-            DeferCleanup(topLevel.AddDisposableHandler(PointerPressedEvent, PointerPressedOutside, RoutingStrategies.Tunnel));
-
             DeferCleanup(InputManager.Instance?.Process.Subscribe(ListenForNonClientClick));
 
             var cleanupPopup = Disposable.Create((popupHost, handlerCleanup), state =>
@@ -384,6 +440,29 @@ namespace Avalonia.Controls.Primitives
                 state.popupHost.Dispose();
             });
 
+            if (IsLightDismissEnabled)
+            {
+                var dismissLayer = LightDismissOverlayLayer.GetLightDismissOverlayLayer(placementTarget);
+
+                if (dismissLayer != null)
+                {
+                    dismissLayer.IsVisible = true;
+                    dismissLayer.InputPassThroughElement = _overlayInputPassThroughElement;
+                    
+                    DeferCleanup(Disposable.Create(() =>
+                    {
+                        dismissLayer.IsVisible = false;
+                        dismissLayer.InputPassThroughElement = null;
+                    }));
+                    
+                    DeferCleanup(SubscribeToEventHandler<LightDismissOverlayLayer, EventHandler<PointerPressedEventArgs>>(
+                        dismissLayer,
+                        PointerPressedDismissOverlay,
+                        (x, handler) => x.PointerPressed += handler,
+                        (x, handler) => x.PointerPressed -= handler));
+                }
+            }
+
             _openState = new PopupOpenState(topLevel, popupHost, cleanupPopup);
 
             WindowManagerAddShadowHintChanged(popupHost, WindowManagerAddShadowHint);
@@ -401,7 +480,7 @@ namespace Avalonia.Controls.Primitives
         /// <summary>
         /// Closes the popup.
         /// </summary>
-        public void Close() => CloseCore(null);
+        public void Close() => CloseCore();
 
         /// <summary>
         /// Measures the control.
@@ -471,7 +550,7 @@ namespace Avalonia.Controls.Primitives
             }
         }
 
-        private void CloseCore(EventArgs? closeEvent)
+        private void CloseCore()
         {
             if (_openState is null)
             {
@@ -491,24 +570,46 @@ namespace Avalonia.Controls.Primitives
                 IsOpen = false;
             }
 
-            Closed?.Invoke(this, new PopupClosedEventArgs(closeEvent));
+            Closed?.Invoke(this, EventArgs.Empty);
         }
 
         private void ListenForNonClientClick(RawInputEventArgs e)
         {
             var mouse = e as RawPointerEventArgs;
 
-            if (!StaysOpen && mouse?.Type == RawPointerEventType.NonClientLeftButtonDown)
+            if (IsLightDismissEnabled && mouse?.Type == RawPointerEventType.NonClientLeftButtonDown)
             {
-                CloseCore(e);
+                CloseCore();
             }
         }
 
-        private void PointerPressedOutside(object sender, PointerPressedEventArgs e)
+        private void PointerPressedDismissOverlay(object sender, PointerPressedEventArgs e)
         {
-            if (!StaysOpen && e.Source is IVisual v && !IsChildOrThis(v))
+            if (IsLightDismissEnabled && e.Source is IVisual v && !IsChildOrThis(v))
             {
-                CloseCore(e);
+                CloseCore();
+
+                if (OverlayDismissEventPassThrough)
+                {
+                    PassThroughEvent(e);
+                }
+            }
+        }
+
+        private void PassThroughEvent(PointerPressedEventArgs e)
+        {
+            if (e.Source is LightDismissOverlayLayer layer &&
+                layer.GetVisualRoot() is IInputElement root)
+            {
+                var p = e.GetCurrentPoint(root);
+                var hit = root.InputHitTest(p.Position, x => x != layer);
+
+                if (hit != null)
+                {
+                    e.Pointer.Capture(hit);
+                    hit.RaiseEvent(e);
+                    e.Handled = true;
+                }
             }
         }
 
@@ -602,7 +703,7 @@ namespace Avalonia.Controls.Primitives
 
         private void WindowDeactivated(object sender, EventArgs e)
         {
-            if (!StaysOpen)
+            if (IsLightDismissEnabled)
             {
                 Close();
             }
@@ -610,7 +711,7 @@ namespace Avalonia.Controls.Primitives
 
         private void ParentClosed(object sender, EventArgs e)
         {
-            if (!StaysOpen)
+            if (IsLightDismissEnabled)
             {
                 Close();
             }
@@ -618,7 +719,7 @@ namespace Avalonia.Controls.Primitives
         
         private void WindowLostFocus()
         {
-            if(!StaysOpen)
+            if (IsLightDismissEnabled)
                 Close();
         }
 

src/Avalonia.Controls/Primitives/PopupClosedEventArgs.cs

@@ -1,33 +0,0 @@
-using System;
-using Avalonia.Interactivity;
-
-#nullable enable
-
-namespace Avalonia.Controls.Primitives
-{
-    /// <summary>
-    /// Holds data for the <see cref="Popup.Closed"/> event.
-    /// </summary>
-    public class PopupClosedEventArgs : EventArgs
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="PopupClosedEventArgs"/> class.
-        /// </summary>
-        /// <param name="closeEvent"></param>
-        public PopupClosedEventArgs(EventArgs? closeEvent)
-        {
-            CloseEvent = closeEvent;
-        }
-
-        /// <summary>
-        /// Gets the event that closed the popup, if any.
-        /// </summary>
-        /// <remarks>
-        /// If <see cref="Popup.StaysOpen"/> is false, then this property will hold details of the
-        /// interaction that caused the popup to close if the close was caused by e.g. a pointer press
-        /// outside the popup. It can be used to mark the event as handled if the event should not
-        /// be propagated.
-        /// </remarks>
-        public EventArgs? CloseEvent { get; }
-    }
-}

src/Avalonia.Controls/Primitives/VisualLayerManager.cs

@@ -1,6 +1,6 @@
 using System.Collections.Generic;
 using Avalonia.LogicalTree;
-using Avalonia.Metadata;
+using Avalonia.Media;
 
 namespace Avalonia.Controls.Primitives
 {
@@ -8,7 +8,8 @@ namespace Avalonia.Controls.Primitives
     {
         private const int AdornerZIndex = int.MaxValue - 100;
         private const int ChromeZIndex = int.MaxValue - 99;
-        private const int OverlayZIndex = int.MaxValue - 98;
+        private const int LightDismissOverlayZIndex = int.MaxValue - 98;
+        private const int OverlayZIndex = int.MaxValue - 97;
 
         private ILogicalRoot _logicalRoot;
         private readonly List<Control> _layers = new List<Control>();
@@ -62,6 +63,27 @@ namespace Avalonia.Controls.Primitives
             }
         }
 
+        public LightDismissOverlayLayer LightDismissOverlayLayer
+        {
+            get
+            {
+                if (IsPopup)
+                    return null;
+                var rv = FindLayer<LightDismissOverlayLayer>();
+                if (rv == null)
+                {
+                    rv = new LightDismissOverlayLayer
+                    {
+                        Background = Brushes.Transparent,
+                        IsVisible = false
+                    };
+
+                    AddLayer(rv, LightDismissOverlayZIndex);
+                }
+                return rv;
+            }
+        }
+
         T FindLayer<T>() where T : class
         {
             foreach (var layer in _layers)

src/Avalonia.Controls/Utils/SelectedItemsSync.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Specialized;
+using System.ComponentModel;
 using System.Linq;
 using Avalonia.Collections;
 
@@ -16,6 +17,7 @@ namespace Avalonia.Controls.Utils
         private IList? _items;
         private bool _updatingItems;
         private bool _updatingModel;
+        private bool _initializeOnSourceAssignment;
 
         public SelectedItemsSync(ISelectionModel model)
         {
@@ -63,10 +65,18 @@ namespace Avalonia.Controls.Utils
                 _updatingModel = true;
                 _items = items;
 
-                using (Model.Update())
+                if (Model.Source is object)
                 {
-                    Model.ClearSelection();
-                    Add(items);
+                    using (Model.Update())
+                    {
+                        Model.ClearSelection();
+                        Add(items);
+                    }
+                }
+                else if (!_initializeOnSourceAssignment)
+                {
+                    Model.PropertyChanged += SelectionModelPropertyChanged;
+                    _initializeOnSourceAssignment = true;
                 }
 
                 if (_items is INotifyCollectionChanged incc2)
@@ -86,9 +96,11 @@ namespace Avalonia.Controls.Utils
 
             if (_items != null)
             {
+                Model.PropertyChanged -= SelectionModelPropertyChanged;
                 Model.SelectionChanged -= SelectionModelSelectionChanged;
                 Model = model;
                 Model.SelectionChanged += SelectionModelSelectionChanged;
+                _initializeOnSourceAssignment = false;
 
                 try
                 {
@@ -175,6 +187,25 @@ namespace Avalonia.Controls.Utils
             }
         }
 
+        private void SelectionModelPropertyChanged(object sender, PropertyChangedEventArgs e)
+        {
+            if (_initializeOnSourceAssignment &&
+                _items != null &&
+                e.PropertyName == nameof(SelectionModel.Source))
+            {
+                try
+                {
+                    _updatingModel = true;
+                    Add(_items);
+                    _initializeOnSourceAssignment = false;
+                }
+                finally
+                {
+                    _updatingModel = false;
+                }
+            }
+        }
+
         private void SelectionModelSelectionChanged(object sender, SelectionModelSelectionChangedEventArgs e)
         {
             if (_updatingModel)

src/Avalonia.DesignerSupport/DesignWindowLoader.cs

@@ -69,6 +69,8 @@ namespace Avalonia.DesignerSupport
                     window = new Window() {Content = (Control)control};
                 }
 
+                Design.ApplyDesignModeProperties(window, control);
+
                 if (!window.IsSet(Window.SizeToContentProperty))
                 {
                     if (double.IsNaN(window.Width))
@@ -83,7 +85,6 @@ namespace Avalonia.DesignerSupport
                 }
             }
             window.Show();
-            Design.ApplyDesignModeProperties(window, control);
             return window;
         }
     }

src/Avalonia.Input/InputExtensions.cs

@@ -3,6 +3,8 @@ using System.Collections.Generic;
 using System.Linq;
 using Avalonia.VisualTree;
 
+#nullable enable
+
 namespace Avalonia.Input
 {
     /// <summary>
@@ -22,7 +24,7 @@ namespace Avalonia.Input
         /// </returns>
         public static IEnumerable<IInputElement> GetInputElementsAt(this IInputElement element, Point p)
         {
-            Contract.Requires<ArgumentNullException>(element != null);
+            element = element ?? throw new ArgumentNullException(nameof(element));
 
             return element.GetVisualsAt(p, s_hitTestDelegate).Cast<IInputElement>();
         }
@@ -33,13 +35,34 @@ namespace Avalonia.Input
         /// <param name="element">The element to test.</param>
         /// <param name="p">The point on <paramref name="element"/>.</param>
         /// <returns>The topmost <see cref="IInputElement"/> at the specified position.</returns>
-        public static IInputElement InputHitTest(this IInputElement element, Point p)
+        public static IInputElement? InputHitTest(this IInputElement element, Point p)
         {
-            Contract.Requires<ArgumentNullException>(element != null);
+            element = element ?? throw new ArgumentNullException(nameof(element));
 
             return element.GetVisualAt(p, s_hitTestDelegate) as IInputElement;
         }
 
+        /// <summary>
+        /// Returns the topmost active input element at a point on an <see cref="IInputElement"/>.
+        /// </summary>
+        /// <param name="element">The element to test.</param>
+        /// <param name="p">The point on <paramref name="element"/>.</param>
+        /// <param name="filter">
+        /// A filter predicate. If the predicate returns false then the visual and all its
+        /// children will be excluded from the results.
+        /// </param>
+        /// <returns>The topmost <see cref="IInputElement"/> at the specified position.</returns>
+        public static IInputElement? InputHitTest(
+            this IInputElement element,
+            Point p,
+            Func<IVisual, bool> filter)
+        {
+            element = element ?? throw new ArgumentNullException(nameof(element));
+            filter = filter ?? throw new ArgumentNullException(nameof(filter));
+
+            return element.GetVisualAt(p, x => s_hitTestDelegate(x) && filter(x)) as IInputElement;
+        }
+
         private static bool IsHitTestVisible(IVisual visual)
         {
             var element = visual as IInputElement;

src/Avalonia.Themes.Default/Accents/BaseDark.xaml

@@ -58,6 +58,9 @@
         <SolidColorBrush x:Key="NotificationCardWarningBackgroundBrush" Color="#FDB328" Opacity="0.75"/>
         <SolidColorBrush x:Key="NotificationCardErrorBackgroundBrush" Color="#BD202C" Opacity="0.75"/>
 
+        <SolidColorBrush x:Key="DatePickerFlyoutPresenterHighlightFill" Color="{DynamicResource ThemeAccentColor}" Opacity="0.4" />
+        <SolidColorBrush x:Key="TimePickerFlyoutPresenterHighlightFill" Color="{DynamicResource ThemeAccentColor}" Opacity="0.4" />
+
         <SolidColorBrush x:Key="ThemeControlTransparentBrush" Color="Transparent" />
       
         <Thickness x:Key="ThemeBorderThickness">1,1,1,1</Thickness>

src/Avalonia.Themes.Default/Accents/BaseLight.xaml

@@ -61,6 +61,9 @@
         <SolidColorBrush x:Key="NotificationCardWarningBackgroundBrush" Color="#FDB328" Opacity="0.75"/>
         <SolidColorBrush x:Key="NotificationCardErrorBackgroundBrush" Color="#BD202C" Opacity="0.75"/>
 
+        <SolidColorBrush x:Key="DatePickerFlyoutPresenterHighlightFill" Color="{DynamicResource ThemeAccentColor}" Opacity="0.4" />
+        <SolidColorBrush x:Key="TimePickerFlyoutPresenterHighlightFill" Color="{DynamicResource ThemeAccentColor}" Opacity="0.4" />
+      
         <SolidColorBrush x:Key="ThemeControlTransparentBrush" Color="Transparent" />
 
         <Thickness x:Key="ThemeBorderThickness">1</Thickness>

src/Avalonia.Themes.Default/AutoCompleteBox.xaml

@@ -19,7 +19,7 @@
                  MinWidth="{Binding Bounds.Width, RelativeSource={RelativeSource TemplatedParent}}"
                  MaxHeight="{TemplateBinding MaxDropDownHeight}"
                  PlacementTarget="{TemplateBinding}"
-                 StaysOpen="False">
+                 IsLightDismissEnabled="True">
             <Border BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                     BorderThickness="1">
               <ListBox Name="PART_SelectingItemsControl"

src/Avalonia.Themes.Default/ComboBox.xaml

@@ -66,7 +66,7 @@
                    MinWidth="{Binding Bounds.Width, RelativeSource={RelativeSource TemplatedParent}}"
                    MaxHeight="{TemplateBinding MaxDropDownHeight}"
                    PlacementTarget="{TemplateBinding}"
-                   StaysOpen="False">
+                   IsLightDismissEnabled="True">
               <Border BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                       BorderThickness="1">
                 <ScrollViewer>

src/Avalonia.Themes.Default/DatePicker.xaml

@@ -0,0 +1,334 @@
+<!--
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+-->
+
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:sys="clr-namespace:System;assembly=netstandard">
+  <Styles.Resources>
+    <Thickness x:Key="DatePickerTopHeaderMargin">0,0,0,4</Thickness>
+    <x:Double x:Key="DatePickerFlyoutPresenterHighlightHeight">40</x:Double>
+    <x:Double x:Key="DatePickerFlyoutPresenterItemHeight">40</x:Double>
+    <x:Double x:Key="DatePickerFlyoutPresenterAcceptDismissHostGridHeight">41</x:Double>
+    <x:Double x:Key="DatePickerThemeMinWidth">296</x:Double>
+    <x:Double x:Key="DatePickerThemeMaxWidth">456</x:Double>
+    <Thickness x:Key="DatePickerFlyoutPresenterItemPadding">0,3,0,6</Thickness>
+    <Thickness x:Key="DatePickerFlyoutPresenterMonthPadding">9,3,0,6</Thickness>
+    <Thickness x:Key="DatePickerHostPadding">0,3,0,6</Thickness>
+    <Thickness x:Key="DatePickerHostMonthPadding">9,3,0,6</Thickness>
+    <x:Double x:Key="DatePickerSpacerThemeWidth">1</x:Double>
+  </Styles.Resources>
+
+  <!-- Styles for the items displayed in the selectors -->
+  <Style Selector="ListBoxItem.DateTimePickerItem">
+    <Setter Property="Padding" Value="{DynamicResource DatePickerFlyoutPresenterItemPadding}"/>
+    <Setter Property="VerticalContentAlignment" Value="Center" />
+    <Setter Property="HorizontalContentAlignment" Value="Center" />
+  </Style>
+  <Style Selector="ListBoxItem.DateTimePickerItem:selected">
+    <Setter Property="IsHitTestVisible" Value="False"/>
+  </Style>
+  <Style Selector="ListBoxItem.DateTimePickerItem:selected /template/ Rectangle#PressedBackground">
+    <Setter Property="Fill" Value="Transparent"/>
+  </Style>
+  <Style Selector="ListBoxItem.DateTimePickerItem:selected /template/ ContentPresenter">
+    <Setter Property="Background" Value="Transparent" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+  <Style Selector="ListBoxItem.DateTimePickerItem.MonthItem">
+    <Setter Property="Padding" Value="{DynamicResource DatePickerFlyoutPresenterMonthPadding}"/>
+    <Setter Property="VerticalContentAlignment" Value="Center" />
+    <Setter Property="HorizontalContentAlignment" Value="Left" />
+  </Style>
+
+
+  <!-- This is used for both the accept/dismiss & repeatbuttons in the presenter-->
+  <Style Selector=":is(Button).DateTimeFlyoutButtonStyle">
+    <Setter Property="Background" Value="{DynamicResource ThemeControlTransparentBrush}" />  
+    <Setter Property="HorizontalContentAlignment" Value="Center"/>
+    <Setter Property="VerticalContentAlignment" Value="Center"/>
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Border Background="{TemplateBinding Background}">
+          <ContentPresenter x:Name="ContentPresenter"
+                  Background="{TemplateBinding Background}"
+                  BorderBrush="{DynamicResource ThemeControlTransparentBrush}"
+                  BorderThickness="{DynamicResource DateTimeFlyoutButtonBorderThickness}"
+                  Content="{TemplateBinding Content}"
+                  TextBlock.Foreground="{DynamicResource ThemeForegroundBrush}"
+                  ContentTemplate="{TemplateBinding ContentTemplate}"
+                  Padding="{TemplateBinding Padding}"
+                  HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                  VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
+        </Border>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector=":is(Button).DateTimeFlyoutButtonStyle:pointerover /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ThemeControlHighlightLowBrush}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeControlTransparentBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+
+  <Style Selector=":is(Button).DateTimeFlyoutButtonStyle:pressed /template/ ContentPresenter">
+    <Setter Property="Background" Value="{DynamicResource ThemeControlHighlightMidBrush}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeControlTransparentBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+
+
+  <Style Selector="RepeatButton.UpButton">
+    <Setter Property="VerticalAlignment" Value="Top"/>
+    <Setter Property="Height" Value="22" />
+    <Setter Property="HorizontalAlignment" Value="Stretch" />
+    <Setter Property="Focusable" Value="False" />
+    <Setter Property="Background" Value="{DynamicResource ThemeControlHighlightLowBrush}" />
+    <Setter Property="Content">
+      <Template>
+        <Viewbox Height="10" Width="10" HorizontalAlignment="Center" VerticalAlignment="Center">
+          <Path Stroke="{Binding $parent[RepeatButton].Foreground}" StrokeThickness="1" Data="M 0,9 L 9,0 L 18,9"/>
+        </Viewbox>
+      </Template>
+    </Setter>
+  </Style>
+  <Style Selector="RepeatButton.DownButton">
+    <Setter Property="VerticalAlignment" Value="Bottom"/>
+    <Setter Property="Height" Value="22" />
+    <Setter Property="HorizontalAlignment" Value="Stretch" />
+    <Setter Property="Focusable" Value="False" />
+    <Setter Property="Background" Value="{DynamicResource ThemeControlHighlightLowBrush}" />
+    <Setter Property="Content">
+      <Template>
+        <Viewbox Height="10" Width="10" HorizontalAlignment="Center" VerticalAlignment="Center">
+          <Path Stroke="{Binding $parent[RepeatButton].Foreground}" StrokeThickness="1" Data="M 0,0 L 9,9 L 18,0"/>
+        </Viewbox>
+      </Template>
+    </Setter>
+  </Style>
+
+  <Style Selector="DatePicker">    
+    <Setter Property="FontSize" Value="{DynamicResource FontSizeNormal}" />
+    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}" />
+    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeControlHighlightMidBrush}"/>
+    <Setter Property="BorderThickness" Value="1"/>
+    <Setter Property="HorizontalAlignment" Value="Left" />
+    <Setter Property="VerticalAlignment" Value="Center" />
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Grid Name="LayoutRoot" Margin="{TemplateBinding Padding}" RowDefinitions="Auto,*">
+          <ContentPresenter Name="HeaderContentPresenter" Grid.Row="0"
+                            Content="{TemplateBinding Header}"
+                            ContentTemplate="{TemplateBinding HeaderTemplate}"
+                            Margin="{DynamicResource DatePickerTopHeaderMargin}"
+                            MaxWidth="{DynamicResource DatePickerThemeMaxWidth}"
+                            HorizontalAlignment="Stretch"
+                            VerticalAlignment="Top"/>
+
+          <Button Name="FlyoutButton" Grid.Row="1"
+                  Foreground="{TemplateBinding Foreground}"
+                  Background="{TemplateBinding Background}"
+                  BorderBrush="{TemplateBinding BorderBrush}"
+                  BorderThickness="{TemplateBinding BorderThickness}"
+                  IsEnabled="{TemplateBinding IsEnabled}"
+                  MinWidth="{DynamicResource DatePickerThemeMinWidth}"
+                  MaxWidth="{DynamicResource DatePickerThemeMaxWidth}"
+                  HorizontalAlignment="Stretch"
+                  VerticalAlignment="Stretch"
+                  HorizontalContentAlignment="Stretch"
+                  VerticalContentAlignment="Stretch"
+                  TemplatedControl.IsTemplateFocusTarget="True">
+            <Button.Template>
+              <ControlTemplate>
+                <ContentPresenter Name="ContentPresenter"
+                                  BorderBrush="{TemplateBinding BorderBrush}"
+                                  Background="{TemplateBinding Background}"
+                                  BorderThickness="{TemplateBinding BorderThickness}"
+                                  Content="{TemplateBinding Content}"
+                                  TextBlock.Foreground="{TemplateBinding Foreground}"
+                                  HorizontalContentAlignment="Stretch"
+                                  VerticalContentAlignment="Stretch"/>
+              </ControlTemplate>
+            </Button.Template>
+            <Grid Name="ButtonContentGrid" ColumnDefinitions="78*,Auto,132*,Auto,78*">
+              <TextBlock Name="DayText" Text="day" HorizontalAlignment="Center"
+                         Padding="{DynamicResource DatePickerHostPadding}"
+                         FontFamily="{TemplateBinding FontFamily}"
+                         FontWeight="{TemplateBinding FontWeight}"
+                         FontSize="{TemplateBinding FontSize}"/>
+              <TextBlock Name="MonthText" Text="month" TextAlignment="Left"
+                         Padding="{DynamicResource DatePickerHostMonthPadding}"
+                         FontFamily="{TemplateBinding FontFamily}"
+                         FontWeight="{TemplateBinding FontWeight}"
+                         FontSize="{TemplateBinding FontSize}"/>
+              <TextBlock Name="YearText" Text="year" HorizontalAlignment="Center"
+                         Padding="{DynamicResource DatePickerHostPadding}"
+                         FontFamily="{TemplateBinding FontFamily}"
+                         FontWeight="{TemplateBinding FontWeight}"
+                         FontSize="{TemplateBinding FontSize}"/>
+              <Rectangle x:Name="FirstSpacer"
+                    Fill="{DynamicResource ThemeControlMidHighBrush}"
+                    HorizontalAlignment="Center"
+                    Width="1"
+                    Grid.Column="1" />
+              <Rectangle x:Name="SecondSpacer"
+                    Fill="{DynamicResource ThemeControlMidHighBrush}"
+                    HorizontalAlignment="Center"
+                    Width="1"
+                    Grid.Column="3" />
+            </Grid>
+          </Button>
+
+          <Popup Name="Popup" WindowManagerAddShadowHint="False"
+                 StaysOpen="False" PlacementTarget="{TemplateBinding}"
+                 PlacementMode="Bottom">
+            <DatePickerPresenter Name="PickerPresenter" />
+          </Popup>
+
+        </Grid>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+  <Style Selector="DatePicker /template/ ContentPresenter#HeaderContentPresenter">
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+  <Style Selector="DatePicker:disabled /template/ Rectangle">
+    <!--<Setter Property="Fill" Value="{DynamicResource DatePickerSpacerFillDisabled}"/>-->
+    <Setter Property="Opacity" Value="{DynamicResource ThemeDisabledOpacity}" />
+  </Style>
+
+  <Style Selector="DatePicker /template/ Button#FlyoutButton:pointerover /template/ ContentPresenter">
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeControlHighBrush}"/>
+    <!--<Setter Property="Background" Value="{DynamicResource DatePickerButtonBackgroundPointerOver}"/>-->
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+
+  <Style Selector="DatePicker /template/ Button#FlyoutButton:pressed /template/ ContentPresenter">
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeControlLowBrush}"/>
+    <Setter Property="Background">
+      <SolidColorBrush Color="{DynamicResource ThemeControlMidHighColor}" Opacity="0.6" />
+    </Setter>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+
+  <Style Selector="DatePicker /template/ Button#FlyoutButton:disabled /template/ ContentPresenter">
+    <!--<Setter Property="BorderBrush" Value="{DynamicResource DatePickerButtonBorderBrushDisabled}"/>
+    <Setter Property="Background" Value="{DynamicResource DatePickerButtonBackgroundDisabled}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource DatePickerButtonForegroundDisabled}"/>-->
+    <Setter Property="Opacity" Value="{DynamicResource ThemeDisabledOpacity}" />
+  </Style>
+
+  <!-- Changes foreground for watermark text when SelectedDate is null-->
+  <Style Selector="DatePicker:hasnodate /template/ Button#FlyoutButton TextBlock">
+    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundLowBrush}"/>
+  </Style>
+
+  <!--WinUI: DatePickerFlyoutPresenter-->
+  <Style Selector="DatePickerPresenter">
+    <Setter Property="Width" Value="296" />
+    <Setter Property="MinWidth" Value="296" />
+    <Setter Property="MaxHeight" Value="398" />    
+    <Setter Property="FontWeight" Value="Normal" />
+    <Setter Property="FontSize" Value="{DynamicResource FontSizeNormal}" />
+    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}" />
+    <Setter Property="BorderThickness" Value="{DynamicResource DateTimeFlyoutBorderThickness}" />
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Border Name="Background" Background="{TemplateBinding Background}"
+                BorderBrush="{TemplateBinding BorderBrush}"
+                BorderThickness="{TemplateBinding BorderThickness}"
+                Padding="{DynamicResource DateTimeFlyoutBorderPadding}"
+                MaxHeight="398">
+          <Grid Name="ContentRoot" RowDefinitions="*,Auto">
+            <Grid Name="PickerContainer">
+              <!--Column Definitions set in code, ignore here-->
+              <Panel Name="MonthHost">
+                <ScrollViewer HorizontalScrollBarVisibility="Disabled"
+                              VerticalScrollBarVisibility="Hidden">
+                  <DateTimePickerPanel Name="MonthSelector"
+                                      PanelType="Month"
+                                      ItemHeight="{DynamicResource DatePickerFlyoutPresenterItemHeight}"
+                                      ShouldLoop="True" />
+                </ScrollViewer>
+                <RepeatButton Name="MonthUpButton"
+                              Classes="DateTimeFlyoutButtonStyle UpButton"/>
+                <RepeatButton Name="MonthDownButton"
+                              Classes="DateTimeFlyoutButtonStyle DownButton"/>
+              </Panel>
+              <Panel Name="DayHost">
+                <ScrollViewer HorizontalScrollBarVisibility="Disabled"
+                              VerticalScrollBarVisibility="Hidden">
+                  <DateTimePickerPanel Name="DaySelector"
+                                      PanelType="Day"
+                                      ItemHeight="{DynamicResource DatePickerFlyoutPresenterItemHeight}"
+                                      ShouldLoop="True" />
+                </ScrollViewer>
+                <RepeatButton Name="DayUpButton"
+                              Classes="DateTimeFlyoutButtonStyle UpButton"/>
+                <RepeatButton Name="DayDownButton"
+                              Classes="DateTimeFlyoutButtonStyle DownButton"/>
+              </Panel>
+              <Panel Name="YearHost">
+                <ScrollViewer HorizontalScrollBarVisibility="Disabled"
+                              VerticalScrollBarVisibility="Hidden">
+                  <DateTimePickerPanel Name="YearSelector"
+                                      PanelType="Year"
+                                      ItemHeight="{DynamicResource DatePickerFlyoutPresenterItemHeight}"
+                                      ShouldLoop="False" />
+                </ScrollViewer>
+                <RepeatButton Name="YearUpButton"
+                              Classes="DateTimeFlyoutButtonStyle UpButton"/>
+                <RepeatButton Name="YearDownButton"
+                              Classes="DateTimeFlyoutButtonStyle DownButton"/>
+              </Panel>
+              <Rectangle Name="HighlightRect" IsHitTestVisible="False" ZIndex="-1"
+                         Fill="{DynamicResource DatePickerFlyoutPresenterHighlightFill}"
+                         Grid.Column="0" Grid.ColumnSpan="5" VerticalAlignment="Center"
+                         Height="{DynamicResource DatePickerFlyoutPresenterHighlightHeight}" />
+              <Rectangle Name="FirstSpacer"
+                         Fill="{DynamicResource ThemeControlMidHighBrush}"
+                         HorizontalAlignment="Center"
+                         Width="{DynamicResource DatePickerSpacerThemeWidth}"
+                         Grid.Column="1" />
+              <Rectangle Name="SecondSpacer"
+                         Fill="{DynamicResource ThemeControlMidHighBrush}"
+                         HorizontalAlignment="Center"
+                         Width="{DynamicResource DatePickerSpacerThemeWidth}"
+                         Grid.Column="3" />
+            </Grid>
+            <Grid Grid.Row="1" Height="{DynamicResource DatePickerFlyoutPresenterAcceptDismissHostGridHeight}"
+                  Name="AcceptDismissGrid" ColumnDefinitions="*,*">
+              <Rectangle Height="{DynamicResource DatePickerSpacerThemeWidth}" VerticalAlignment="Top"
+                         Fill="{DynamicResource ThemeControlMidHighBrush}"
+                         Grid.ColumnSpan="2"/>
+              <Button Name="AcceptButton" Grid.Column="0" Classes="DateTimeFlyoutButtonStyle"
+                          HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
+                <Path Stroke="{Binding $parent[Button].Foreground}" StrokeLineCap="Round"
+                      StrokeThickness="0.75" Data="M0.5,8.5 5,13.5 15.5,3" />
+              </Button>
+              <Button Name="DismissButton" Grid.Column="1" Classes="DateTimeFlyoutButtonStyle"
+                         FontSize="16" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
+                <Path Stroke="{Binding $parent[Button].Foreground}" StrokeLineCap="Round"
+                      StrokeThickness="0.75" Data="M2,2 14,14 M2,14 14 2" />
+              </Button>
+            </Grid>
+          </Grid>
+        </Border>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="DatePickerPresenter /template/ Panel RepeatButton">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+
+  <Style Selector="DatePickerPresenter /template/ Panel:pointerover RepeatButton">
+    <Setter Property="IsVisible" Value="True" />
+  </Style>
+  
+</Styles>

src/Avalonia.Themes.Default/DefaultTheme.xaml

@@ -55,4 +55,7 @@
   <StyleInclude Source="resm:Avalonia.Themes.Default.NotificationCard.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.NativeMenuBar.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.ToggleSwitch.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.SplitView.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.DatePicker.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.TimePicker.xaml?assembly=Avalonia.Themes.Default"/>
 </Styles>

src/Avalonia.Themes.Default/GridSplitter.xaml

@@ -2,8 +2,8 @@
 
   <Style Selector="GridSplitter">
     <Setter Property="Focusable" Value="True" />
-    <Setter Property="MinWidth" Value="6" />
-    <Setter Property="MinHeight" Value="6" />
+    <Setter Property="MinWidth" Value="1" />
+    <Setter Property="MinHeight" Value="1" />
     <Setter Property="Background" Value="{DynamicResource ThemeControlMidBrush}" />
     <Setter Property="PreviewContent">
       <Template>

src/Avalonia.Themes.Default/MenuItem.xaml

@@ -59,7 +59,7 @@
                   Grid.Column="4"/>
             <Popup Name="PART_Popup"
                    PlacementMode="Right"
-                   StaysOpen="True"
+                   IsLightDismissEnabled="True"
                    IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
               <Border Background="{TemplateBinding Background}"
                       BorderBrush="{DynamicResource ThemeBorderMidBrush}"
@@ -108,8 +108,8 @@
               </ContentPresenter.DataTemplates>
             </ContentPresenter>
             <Popup Name="PART_Popup"
-                   IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}"
-                   StaysOpen="True">
+                   IsLightDismissEnabled="True"
+                   IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
               <Border Background="{TemplateBinding Background}"
                       BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                       BorderThickness="{TemplateBinding BorderThickness}">

src/Avalonia.Themes.Default/SplitView.xaml

@@ -0,0 +1,219 @@
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+
+  <Styles.Resources>
+    <x:Double x:Key="SplitViewOpenPaneThemeLength">320</x:Double>
+    <x:Double x:Key="SplitViewCompactPaneThemeLength">48</x:Double>
+
+    <!-- Not used here (directly) since they're strings, but preserving for reference
+        <x:String x:Key="SplitViewPaneAnimationOpenDuration">00:00:00.2</x:String>
+        <x:String x:Key="SplitViewPaneAnimationOpenPreDuration">00:00:00.19999</x:String>
+        <x:String x:Key="SplitViewPaneAnimationCloseDuration">00:00:00.1</x:String>-->
+  </Styles.Resources>
+
+  <Style Selector="SplitView">
+    <Setter Property="OpenPaneLength" Value="{DynamicResource SplitViewOpenPaneThemeLength}" />
+    <Setter Property="CompactPaneLength" Value="{DynamicResource SplitViewCompactPaneThemeLength}" />
+    <Setter Property="PaneBackground" Value="{DynamicResource ThemeControlHighlightLowBrush}" />
+  </Style>
+
+  <!-- Left -->
+  <Style Selector="SplitView:left">
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Grid Name="Container" Background="{TemplateBinding Background}">
+          <Grid.ColumnDefinitions>
+            <!-- why is this throwing a binding error? -->
+            <ColumnDefinition Width="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.PaneColumnGridLength}"/>
+            <ColumnDefinition Width="*"/>
+          </Grid.ColumnDefinitions>
+
+          <Panel Name="PART_PaneRoot" Background="{TemplateBinding PaneBackground}"
+                 ClipToBounds="True"
+                 HorizontalAlignment="Left"
+                 ZIndex="100">
+            <Border Child="{TemplateBinding Pane}"/>
+            <Rectangle Name="HCPaneBorder" Fill="{DynamicResource SystemControlForegroundTransparentBrush}" Width="1" HorizontalAlignment="Right"  />
+          </Panel>
+
+          <Panel Name="ContentRoot">
+            <Border Child="{TemplateBinding Content}" />
+            <Rectangle Name="LightDismissLayer"/>
+          </Panel>
+
+        </Grid>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <!-- Overlay -->
+  <Style Selector="SplitView:overlay:left /template/ Panel#PART_PaneRoot">
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.ClosedPaneWidth}" />
+    <!-- ColumnSpan should be 2 -->
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+    <Setter Property="Grid.Column" Value="0"/>
+  </Style>
+  <Style Selector="SplitView:overlay:left /template/ Panel#ContentRoot">
+    <Setter Property="Grid.Column" Value="1"/>
+    <Setter Property="Grid.ColumnSpan" Value="2"/>
+  </Style>
+
+  <!-- CompactInline -->
+  <Style Selector="SplitView:compactinline:left /template/ Panel#PART_PaneRoot">
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+    <Setter Property="Grid.Column" Value="0"/>
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.ClosedPaneWidth}" />
+  </Style>
+  <Style Selector="SplitView:compactinline:left /template/ Panel#ContentRoot">
+    <Setter Property="Grid.Column" Value="1"/>
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+  </Style>
+
+  <!-- CompactOverlay -->
+  <Style Selector="SplitView:compactoverlay:left /template/ Panel#PART_PaneRoot">
+    <!-- ColumnSpan should be 2 -->
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+    <Setter Property="Grid.Column" Value="0"/>
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.ClosedPaneWidth}" />
+  </Style>
+  <Style Selector="SplitView:compactoverlay:left /template/ Panel#ContentRoot">
+    <Setter Property="Grid.Column" Value="1"/>
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+  </Style>
+
+  <!-- Inline -->
+  <Style Selector="SplitView:inline:left /template/ Panel#PART_PaneRoot">
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+    <Setter Property="Grid.Column" Value="0"/>
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.ClosedPaneWidth}" />
+  </Style>
+  <Style Selector="SplitView:inline:left /template/ Panel#ContentRoot">
+    <Setter Property="Grid.Column" Value="1"/>
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+  </Style>
+
+  <!-- Right -->
+  <Style Selector="SplitView:right">
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Grid Name="Container" Background="{TemplateBinding Background}">
+          <Grid.ColumnDefinitions>
+            <ColumnDefinition Width="*"/>
+            <ColumnDefinition Width="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.PaneColumnGridLength}"/>
+          </Grid.ColumnDefinitions>
+
+          <Panel Name="PART_PaneRoot" Background="{TemplateBinding PaneBackground}"
+                 ClipToBounds="True"
+                 HorizontalAlignment="Right"
+                 ZIndex="100">
+            <Border Child="{TemplateBinding Pane}"/>
+            <Rectangle Name="HCPaneBorder"
+                       Fill="{DynamicResource SystemControlForegroundTransparentBrush}"
+                       Width="1" HorizontalAlignment="Left"  />
+          </Panel>
+
+          <Panel Name="ContentRoot">
+            <Border Child="{TemplateBinding Content}" />
+            <Rectangle Name="LightDismissLayer"/>
+          </Panel>
+
+        </Grid>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <!-- Overlay -->
+  <Style Selector="SplitView:overlay:right /template/ Panel#PART_PaneRoot">
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.ClosedPaneWidth}" />
+    <Setter Property="Grid.ColumnSpan" Value="2"/>
+    <Setter Property="Grid.Column" Value="1"/>
+  </Style>
+  <Style Selector="SplitView:overlay:right /template/ Panel#ContentRoot">
+    <Setter Property="Grid.Column" Value="0"/>
+    <Setter Property="Grid.ColumnSpan" Value="2"/>
+  </Style>
+
+  <!-- CompactInline -->
+  <Style Selector="SplitView:compactinline:right /template/ Panel#PART_PaneRoot">
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+    <Setter Property="Grid.Column" Value="1"/>
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.ClosedPaneWidth}" />
+  </Style>
+  <Style Selector="SplitView:compactinline:right /template/ Panel#ContentRoot">
+    <Setter Property="Grid.Column" Value="0"/>
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+  </Style>
+
+  <!-- CompactOverlay -->
+  <Style Selector="SplitView:compactoverlay:right /template/ Panel#PART_PaneRoot">
+    <Setter Property="Grid.ColumnSpan" Value="2"/>
+    <Setter Property="Grid.Column" Value="1"/>
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.ClosedPaneWidth}" />
+  </Style>
+  <Style Selector="SplitView:compactoverlay:right /template/ Panel#ContentRoot">
+    <Setter Property="Grid.Column" Value="0"/>
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+  </Style>
+
+  <!-- Inline -->
+  <Style Selector="SplitView:inline:right /template/ Panel#PART_PaneRoot">
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+    <Setter Property="Grid.Column" Value="1"/>
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.ClosedPaneWidth}" />
+  </Style>
+  <Style Selector="SplitView:inline:right /template/ Panel#ContentRoot">
+    <Setter Property="Grid.Column" Value="0"/>
+    <Setter Property="Grid.ColumnSpan" Value="1"/>
+  </Style>
+
+  <!-- Open/Close Pane animation  -->
+  <Style Selector="SplitView:open /template/ Panel#PART_PaneRoot">
+    <Setter Property="Transitions">
+      <Transitions>
+        <DoubleTransition Property="Width" Duration="00:00:00.2" Easing="0.1,0.9,0.2,1.0" />
+      </Transitions>
+    </Setter>
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=OpenPaneLength}" />
+  </Style>
+  <Style Selector="SplitView:open /template/ Rectangle#LightDismissLayer">
+    <Setter Property="Transitions">
+      <Transitions>
+        <DoubleTransition Property="Opacity" Duration="00:00:00.2" Easing="0.1,0.9,0.2,1.0" />
+      </Transitions>
+    </Setter>
+    <Setter Property="Opacity" Value="1.0"/>
+  </Style>
+
+  <Style Selector="SplitView:closed /template/ Panel#PART_PaneRoot">
+    <Setter Property="Transitions">
+      <Transitions>
+        <DoubleTransition Property="Width" Duration="00:00:00.1" Easing="0.1,0.9,0.2,1.0" />
+      </Transitions>
+    </Setter>
+    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.ClosedPaneWidth}" />
+  </Style>
+  <Style Selector="SplitView:closed /template/ Rectangle#LightDismissLayer">
+    <Setter Property="Transitions">
+      <Transitions>
+        <DoubleTransition Property="Opacity" Duration="00:00:00.2" Easing="0.1,0.9,0.2,1.0" />
+      </Transitions>
+    </Setter>
+    <Setter Property="Opacity" Value="0.0"/>
+  </Style>
+
+  <Style Selector="SplitView /template/ Rectangle#LightDismissLayer">
+    <Setter Property="IsVisible" Value="False"/>
+    <Setter Property="Fill" Value="Transparent" />
+  </Style>
+  <Style Selector="SplitView:lightdismiss /template/ Rectangle#LightDismissLayer">
+    <Setter Property="Fill" Value="{DynamicResource SplitViewLightDismissOverlayBackground}" />
+  </Style>
+
+  <Style Selector="SplitView:overlay:open /template/ Rectangle#LightDismissLayer">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+  <Style Selector="SplitView:compactoverlay:open /template/ Rectangle#LightDismissLayer">
+    <Setter Property="IsVisible" Value="True"/>
+  </Style>
+
+</Styles>

src/Avalonia.Themes.Default/TimePicker.xaml

@@ -0,0 +1,283 @@
+<!--
+// (c) Copyright Microsoft Corporation.
+// This source is subject to the Microsoft Public License (Ms-PL).
+// Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
+// All other rights reserved.
+-->
+
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:sys="clr-namespace:System;assembly=netstandard">
+  <Styles.Resources>
+    <x:Double x:Key="TimePickerFlyoutPresenterItemHeight">40</x:Double>
+    <x:Double x:Key="TimePickerSpacerThemeWidth">1</x:Double>
+    <Thickness x:Key="TimePickerBorderThemeThickness">1</Thickness>
+    <Thickness x:Key="TimePickerTopHeaderMargin">0,0,0,4</Thickness>
+    <x:Double x:Key="TimePickerFlyoutPresenterHighlightHeight">40</x:Double>
+    <x:Double x:Key="TimePickerFlyoutPresenterAcceptDismissHostGridHeight">41</x:Double>
+    <x:Double x:Key="TimePickerThemeMinWidth">242</x:Double>
+    <x:Double x:Key="TimePickerThemeMaxWidth">456</x:Double>
+    <Thickness x:Key="TimePickerFlyoutPresenterItemPadding">0,3,0,6</Thickness>
+    <Thickness x:Key="TimePickerHostPadding">0,3,0,6</Thickness>
+  </Styles.Resources>
+
+  <Style Selector="ListBoxItem.DateTimePickerItem.HourItem">
+    <Setter Property="Padding" Value="{DynamicResource TimePickerFlyoutPresenterItemPadding}" />
+  </Style>
+  <Style Selector="ListBoxItem.DateTimePickerItem.MinuteItem">
+    <Setter Property="Padding" Value="{DynamicResource TimePickerFlyoutPresenterItemPadding}" />
+  </Style>
+  <Style Selector="ListBoxItem.DateTimePickerItem.TimePeriodItem">
+    <Setter Property="Padding" Value="{DynamicResource TimePickerFlyoutPresenterItemPadding}" />
+  </Style>
+
+  <Style Selector="TimePicker">    
+    <Setter Property="FontSize" Value="{DynamicResource FontSizeNormal}" />
+    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}" />
+    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeControlHighlightMidBrush}"/>
+    <Setter Property="BorderThickness" Value="{DynamicResource TimePickerBorderThemeThickness}"/>
+    <Setter Property="HorizontalAlignment" Value="Left" />
+    <Setter Property="VerticalAlignment" Value="Center" />
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Grid Name="LayoutRoot" Margin="{TemplateBinding Padding}" RowDefinitions="Auto,*">
+          <ContentPresenter x:Name="HeaderContentPresenter"
+                 Grid.Row="0"
+                 Content="{TemplateBinding Header}"
+                 ContentTemplate="{TemplateBinding HeaderTemplate}"
+                 Margin="{DynamicResource TimePickerTopHeaderMargin}"
+                 MaxWidth="{DynamicResource TimePickerThemeMaxWidth}"
+                 TextBlock.Foreground="{DynamicResource TimePickerHeaderForeground}"
+                 HorizontalAlignment="Stretch"
+                 VerticalAlignment="Top" />
+
+          <Button x:Name="FlyoutButton"
+                  Grid.Row="1"
+                  Foreground="{TemplateBinding Foreground}"
+                  Background="{TemplateBinding Background}"
+                  BorderBrush="{TemplateBinding BorderBrush}"
+                  BorderThickness="{TemplateBinding BorderThickness}"
+                  IsEnabled="{TemplateBinding IsEnabled}"
+                  MinWidth="{DynamicResource TimePickerThemeMinWidth}"
+                  MaxWidth="{DynamicResource TimePickerThemeMaxWidth}"
+                  HorizontalAlignment="Stretch"
+                  HorizontalContentAlignment="Stretch"
+                  VerticalAlignment="Top"
+                  VerticalContentAlignment="Stretch">
+            <Button.Template>
+              <ControlTemplate>
+                <ContentPresenter Name="ContentPresenter"
+                                BorderBrush="{TemplateBinding BorderBrush}"
+                                Background="{TemplateBinding Background}"
+                                BorderThickness="{TemplateBinding BorderThickness}"
+                                Content="{TemplateBinding Content}"
+                                TextBlock.Foreground="{TemplateBinding Foreground}"
+                                HorizontalContentAlignment="Stretch"
+                                VerticalContentAlignment="Stretch" />
+              </ControlTemplate>
+            </Button.Template>
+
+            <Grid Name="FlyoutButtonContentGrid">
+              <!--Ignore col defs here, set in code-->
+              <Border x:Name="FirstPickerHost" Grid.Column="0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
+                <TextBlock x:Name="HourTextBlock"
+                    HorizontalAlignment="Center"
+                    Padding="{DynamicResource TimePickerHostPadding}"
+                    FontFamily="{TemplateBinding FontFamily}"
+                    FontWeight="{TemplateBinding FontWeight}"
+                    FontSize="{TemplateBinding FontSize}" />
+              </Border>
+
+              <Rectangle Name="FirstColumnDivider"
+                  Fill="{DynamicResource ThemeControlMidHighBrush}"
+                  HorizontalAlignment="Center"
+                  Width="{DynamicResource TimePickerSpacerThemeWidth}"
+                  Grid.Column="1" />
+
+              <Border x:Name="SecondPickerHost" Grid.Column="2" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
+                <TextBlock x:Name="MinuteTextBlock"
+                    HorizontalAlignment="Center"
+                    Padding="{DynamicResource TimePickerHostPadding}"
+                    FontFamily="{TemplateBinding FontFamily}"
+                    FontWeight="{TemplateBinding FontWeight}"
+                    FontSize="{TemplateBinding FontSize}"/>
+              </Border>
+
+              <Rectangle Name="SecondColumnDivider"
+                  Fill="{DynamicResource ThemeControlMidHighBrush}"
+                  HorizontalAlignment="Center"
+                  Width="{DynamicResource TimePickerSpacerThemeWidth}"
+                  Grid.Column="3" />
+
+              <Border x:Name="ThirdPickerHost" Grid.Column="4" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
+                <TextBlock x:Name="PeriodTextBlock"
+                    HorizontalAlignment="Center"
+                    Padding="{DynamicResource TimePickerHostPadding}"
+                    FontFamily="{TemplateBinding FontFamily}"
+                    FontWeight="{TemplateBinding FontWeight}"
+                    FontSize="{TemplateBinding FontSize}" />
+              </Border>
+            </Grid>
+          </Button>
+
+          <Popup Name="Popup" WindowManagerAddShadowHint="False"
+                 StaysOpen="False" PlacementTarget="{TemplateBinding}"
+                 PlacementMode="Bottom">
+            <TimePickerPresenter Name="PickerPresenter" />
+          </Popup>
+
+        </Grid>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="TimePicker:disabled /template/ ContentPresenter#HeaderContentPresenter">
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+  <Style Selector="TimePicker:disabled /template/ Rectangle">
+    <Setter Property="Opacity" Value="{DynamicResource ThemeDisabledOpacity}"/>
+  </Style>
+
+  <Style Selector="TimePicker /template/ Button#FlyoutButton:pointerover /template/ ContentPresenter">
+    <!--<Setter Property="Background" Value="{DynamicResource TimePickerButtonBackgroundPointerOver}"/>-->
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeControlHighBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+
+  <Style Selector="TimePicker /template/ Button:pressed /template/ ContentPresenter">
+    <Setter Property="Background">
+      <SolidColorBrush Color="{DynamicResource ThemeControlMidHighColor}" Opacity="0.6" />
+    </Setter>
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeControlLowBrush}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
+  </Style>
+
+  <Style Selector="TimePicker /template/ Button:disabled /template/ ContentPresenter">
+    <!--<Setter Property="Background" Value="{DynamicResource TimePickerButtonBackgroundDisabled}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource TimePickerButtonBorderBrushDisabled}"/>
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource TimePickerButtonForegroundDisabled}"/>-->
+    <Setter Property="Opacity" Value="{DynamicResource ThemeDisabledOpacity}" />
+  </Style>
+
+  <Style Selector="TimePicker:hasnotime /template/ Button#FlyoutButton TextBlock">
+    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundLowBrush}"/>
+  </Style>
+
+  <Style Selector="TimePickerPresenter">
+    <Setter Property="Width" Value="242" />
+    <Setter Property="MinWidth" Value="242" />
+    <Setter Property="MaxHeight" Value="398" />    
+    <Setter Property="FontWeight" Value="Normal" />
+    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}" />
+    <Setter Property="BorderThickness" Value="{DynamicResource DateTimeFlyoutBorderThickness}" />
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Border Name="Background"
+                Background="{TemplateBinding Background}"
+                BorderBrush="{TemplateBinding BorderBrush}"
+                BorderThickness="{TemplateBinding BorderThickness}"
+                Padding="{DynamicResource DateTimeFlyoutBorderPadding}"
+                MaxHeight="398">
+          <Grid Name="ContentPanel" RowDefinitions="*,Auto">
+            <Grid Name="PickerContainer">
+              <!--Ignore col defs here, set in code-->
+              <Panel Name="HourHost" Grid.Column="0">
+                <ScrollViewer HorizontalScrollBarVisibility="Disabled"
+                              VerticalScrollBarVisibility="Hidden">
+                  <DateTimePickerPanel Name="HourSelector"
+                                          PanelType="Hour"
+                                          ShouldLoop="True"
+                                          ItemHeight="{DynamicResource TimePickerFlyoutPresenterItemHeight}"/>
+                </ScrollViewer>
+                <RepeatButton Name="HourUpButton"
+                              Classes="DateTimeFlyoutButtonStyle UpButton"/>
+                <RepeatButton Name="HourDownButton"
+                              Classes="DateTimeFlyoutButtonStyle DownButton"/>
+
+              </Panel>
+
+              <Panel Name="MinuteHost" Grid.Column="2">
+                <ScrollViewer HorizontalScrollBarVisibility="Disabled"
+                              VerticalScrollBarVisibility="Hidden">
+                  <DateTimePickerPanel Name="MinuteSelector"
+                                          PanelType="Minute"
+                                          ShouldLoop="True"
+                                          ItemHeight="{DynamicResource TimePickerFlyoutPresenterItemHeight}"/>
+                </ScrollViewer>
+                <RepeatButton Name="MinuteUpButton"
+                              Classes="DateTimeFlyoutButtonStyle UpButton"/>
+                <RepeatButton Name="MinuteDownButton"
+                              Classes="DateTimeFlyoutButtonStyle DownButton"/>
+
+              </Panel>
+
+              <Panel Name="PeriodHost" Grid.Column="4">
+                <ScrollViewer HorizontalScrollBarVisibility="Disabled"
+                              VerticalScrollBarVisibility="Hidden">
+                  <DateTimePickerPanel Name="PeriodSelector"
+                                          PanelType="TimePeriod"
+                                          ShouldLoop="False"
+                                          ItemHeight="{DynamicResource TimePickerFlyoutPresenterItemHeight}"/>
+                </ScrollViewer>
+                <RepeatButton Name="PeriodUpButton"
+                              Classes="DateTimeFlyoutButtonStyle UpButton"/>
+                <RepeatButton Name="PeriodDownButton"
+                              Classes="DateTimeFlyoutButtonStyle DownButton"/>
+
+              </Panel>
+
+              <Rectangle x:Name="HighlightRect" ZIndex="-1"
+                      Fill="{DynamicResource TimePickerFlyoutPresenterHighlightFill}"
+                      Grid.Column="0"
+                      Grid.ColumnSpan="5"
+                      VerticalAlignment="Center"
+                      Height="{DynamicResource TimePickerFlyoutPresenterHighlightHeight}" />
+
+              <Rectangle Name="FirstSpacer"
+                  Fill="{DynamicResource ThemeControlMidHighBrush}"
+                  HorizontalAlignment="Center"
+                  Width="{DynamicResource TimePickerSpacerThemeWidth}"
+                  Grid.Column="1" />
+
+              <Rectangle Name="SecondSpacer"
+                  Fill="{DynamicResource ThemeControlMidHighBrush}"
+                  HorizontalAlignment="Center"
+                  Width="{DynamicResource TimePickerSpacerThemeWidth}"
+                  Grid.Column="3" />
+            </Grid>
+
+            <Grid Grid.Row="1" Height="{DynamicResource TimePickerFlyoutPresenterAcceptDismissHostGridHeight}"
+                  Name="AcceptDismissHostGrid" ColumnDefinitions="*,*">
+              <Rectangle Height="{DynamicResource TimePickerSpacerThemeWidth}"
+                      VerticalAlignment="Top"
+                      Fill="{DynamicResource ThemeControlMidHighBrush}"
+                      Grid.ColumnSpan="2" />
+              <Button Name="AcceptButton" Grid.Column="0" Classes="DateTimeFlyoutButtonStyle"
+                          HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
+                <Path Stroke="{Binding $parent[Button].Foreground}" StrokeLineCap="Round"
+                      StrokeThickness="0.75" Data="M0.5,8.5 5,13.5 15.5,3" />
+              </Button>
+              <Button Name="DismissButton" Grid.Column="1" Classes="DateTimeFlyoutButtonStyle"
+                         FontSize="16" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
+                <Path Stroke="{Binding $parent[Button].Foreground}" StrokeLineCap="Round"
+                      StrokeThickness="0.75" Data="M2,2 14,14 M2,14 14 2" />
+              </Button>
+            </Grid>
+
+          </Grid>
+        </Border>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="TimePickerPresenter /template/ Panel RepeatButton">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+
+  <Style Selector="TimePickerPresenter /template/ Panel:pointerover RepeatButton">
+    <Setter Property="IsVisible" Value="True" />
+  </Style>
+  
+</Styles>

src/Avalonia.Themes.Fluent/AutoCompleteBox.xaml

@@ -47,7 +47,7 @@
                  WindowManagerAddShadowHint="False"
                  MinWidth="{Binding Bounds.Width, RelativeSource={RelativeSource TemplatedParent}}"
                  MaxHeight="{TemplateBinding MaxDropDownHeight}"
-                 StaysOpen="False"                 
+                 IsLightDismissEnabled="True"
                  PlacementTarget="{TemplateBinding}">            
             <Border Name="PART_SuggestionsContainer"
                     Padding="{DynamicResource AutoCompleteListMargin}"

src/Avalonia.Themes.Fluent/CalendarDatePicker.xaml

@@ -120,7 +120,7 @@
 
           <Popup Name="PART_Popup"
                  PlacementTarget="{TemplateBinding}"
-                 StaysOpen="False">
+                 IsLightDismissEnabled="True">
             <Calendar Name="PART_Calendar"
                       FirstDayOfWeek="{TemplateBinding FirstDayOfWeek}"
                       IsTodayHighlighted="{TemplateBinding IsTodayHighlighted}"/>

src/Avalonia.Themes.Fluent/ComboBox.xaml

@@ -124,7 +124,7 @@
                  MinWidth="{Binding Bounds.Width, RelativeSource={RelativeSource TemplatedParent}}"
                  MaxHeight="{TemplateBinding MaxDropDownHeight}"
                  PlacementTarget="{TemplateBinding}"
-                 StaysOpen="False">
+                 IsLightDismissEnabled="True">
             <Border x:Name="PopupBorder"
                     Background="{DynamicResource ComboBoxDropDownBackground}"
                     BorderBrush="{DynamicResource ComboBoxDropDownBorderBrush}"

src/Avalonia.Themes.Fluent/DatePicker.xaml

@@ -190,7 +190,7 @@
           </Button>
 
           <Popup Name="Popup" WindowManagerAddShadowHint="False"
-                 StaysOpen="False" PlacementTarget="{TemplateBinding}"
+                 IsLightDismissEnabled="True" PlacementTarget="{TemplateBinding}"
                  PlacementMode="Bottom">
             <DatePickerPresenter Name="PickerPresenter" />
           </Popup>

src/Avalonia.Themes.Fluent/MenuItem.xaml

@@ -112,7 +112,7 @@
                  WindowManagerAddShadowHint="True"
                  PlacementMode="Right"
                  HorizontalOffset="{StaticResource MenuFlyoutSubItemPopupHorizontalOffset}"
-                 StaysOpen="True"
+                 IsLightDismissEnabled="True"
                  IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
             <Border Background="{DynamicResource MenuFlyoutPresenterBackground}"
                     BorderBrush="{DynamicResource MenuFlyoutPresenterBorderBrush}"
@@ -159,8 +159,9 @@
             <Popup Name="PART_Popup"
                    WindowManagerAddShadowHint="False"
                    MinWidth="{Binding Bounds.Width, RelativeSource={RelativeSource TemplatedParent}}"
+                   IsLightDismissEnabled="True"
                    IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}"
-                   StaysOpen="True">
+                   OverlayInputPassThroughElement="{Binding $parent[Menu]}">
               <Border Background="{DynamicResource MenuFlyoutPresenterBackground}"
                       BorderBrush="{DynamicResource MenuFlyoutPresenterBorderBrush}"
                       BorderThickness="{DynamicResource MenuFlyoutPresenterBorderThemeThickness}"

src/Avalonia.Themes.Fluent/TimePicker.xaml

@@ -123,7 +123,7 @@
           </Button>
 
           <Popup Name="Popup" WindowManagerAddShadowHint="False"
-                 StaysOpen="False" PlacementTarget="{TemplateBinding}"
+                 IsLightDismissEnabled="True" PlacementTarget="{TemplateBinding}"
                  PlacementMode="Bottom">
             <TimePickerPresenter Name="PickerPresenter" />
           </Popup>

src/Avalonia.Visuals/Media/TextFormatting/TextFormatterImpl.cs

@@ -31,7 +31,8 @@ namespace Avalonia.Media.TextFormatting
                 case TextWrapping.WrapWithOverflow:
                 case TextWrapping.Wrap:
                     {
-                        textLine = PerformTextWrapping(textRuns, textRange, paragraphWidth, paragraphProperties);
+                        textLine = PerformTextWrapping(textRuns, textRange, paragraphWidth, paragraphProperties,
+                            nextLineBreak);
                         break;
                     }
                 default:
@@ -118,7 +119,7 @@ namespace Avalonia.Media.TextFormatting
         /// <param name="textRuns">The text run's.</param>
         /// <param name="length">The length to split at.</param>
         /// <returns>The split text runs.</returns>
-        internal static SplitTextRunsResult SplitTextRuns(IReadOnlyList<ShapedTextCharacters> textRuns, int length)
+        internal static SplitTextRunsResult SplitTextRuns(List<ShapedTextCharacters> textRuns, int length)
         {
             var currentLength = 0;
 
@@ -134,13 +135,13 @@ namespace Avalonia.Media.TextFormatting
 
                 var firstCount = currentRun.GlyphRun.Characters.Length >= 1 ? i + 1 : i;
 
-                var first = new ShapedTextCharacters[firstCount];
+                var first = new List<ShapedTextCharacters>(firstCount);
 
                 if (firstCount > 1)
                 {
                     for (var j = 0; j < i; j++)
                     {
-                        first[j] = textRuns[j];
+                        first.Add(textRuns[j]);
                     }
                 }
 
@@ -148,7 +149,7 @@ namespace Avalonia.Media.TextFormatting
 
                 if (currentLength + currentRun.GlyphRun.Characters.Length == length)
                 {
-                    var second = new ShapedTextCharacters[secondCount];
+                    var second = new List<ShapedTextCharacters>(secondCount);
 
                     var offset = currentRun.GlyphRun.Characters.Length > 1 ? 1 : 0;
 
@@ -156,11 +157,11 @@ namespace Avalonia.Media.TextFormatting
                     {
                         for (var j = 0; j < secondCount; j++)
                         {
-                            second[j] = textRuns[i + j + offset];
+                            second.Add(textRuns[i + j + offset]);
                         }
                     }
 
-                    first[i] = currentRun;
+                    first.Add(currentRun);
 
                     return new SplitTextRunsResult(first, second);
                 }
@@ -168,22 +169,22 @@ namespace Avalonia.Media.TextFormatting
                 {
                     secondCount++;
 
-                    var second = new ShapedTextCharacters[secondCount];
+                    var second = new List<ShapedTextCharacters>(secondCount);
+
+                    var split = currentRun.Split(length - currentLength);
+
+                    first.Add(split.First);
+
+                    second.Add(split.Second);
 
                     if (secondCount > 0)
                     {
                         for (var j = 1; j < secondCount; j++)
                         {
-                            second[j] = textRuns[i + j];
+                            second.Add(textRuns[i + j]);
                         }
                     }
 
-                    var split = currentRun.Split(length - currentLength);
-
-                    first[i] = split.First;
-
-                    second[0] = split.Second;
-
                     return new SplitTextRunsResult(first, second);
                 }
             }
@@ -201,7 +202,7 @@ namespace Avalonia.Media.TextFormatting
         /// <returns>
         /// The formatted text runs.
         /// </returns>
-        private static IReadOnlyList<ShapedTextCharacters> FetchTextRuns(ITextSource textSource,
+        private static List<ShapedTextCharacters> FetchTextRuns(ITextSource textSource,
             int firstTextSourceIndex, TextLineBreak previousLineBreak, out TextLineBreak nextLineBreak)
         {
             nextLineBreak = default;
@@ -212,8 +213,10 @@ namespace Avalonia.Media.TextFormatting
 
             if (previousLineBreak != null)
             {
-                foreach (var shapedCharacters in previousLineBreak.RemainingCharacters)
+                for (var index = 0; index < previousLineBreak.RemainingCharacters.Count; index++)
                 {
+                    var shapedCharacters = previousLineBreak.RemainingCharacters[index];
+
                     if (shapedCharacters == null)
                     {
                         continue;
@@ -225,6 +228,14 @@ namespace Avalonia.Media.TextFormatting
                     {
                         var splitResult = SplitTextRuns(textRuns, currentLength + runLineBreak.PositionWrap);
 
+                        if (++index < previousLineBreak.RemainingCharacters.Count)
+                        {
+                            for (; index < previousLineBreak.RemainingCharacters.Count; index++)
+                            {
+                                splitResult.Second.Add(previousLineBreak.RemainingCharacters[index]);
+                            }
+                        }
+
                         nextLineBreak = new TextLineBreak(splitResult.Second);
 
                         return splitResult.First;
@@ -323,9 +334,10 @@ namespace Avalonia.Media.TextFormatting
         /// <param name="textRange">The text range that is covered by the text runs.</param>
         /// <param name="paragraphWidth">The paragraph width.</param>
         /// <param name="paragraphProperties">The text paragraph properties.</param>
+        /// <param name="currentLineBreak">The current line break if the line was explicitly broken.</param>
         /// <returns>The wrapped text line.</returns>
-        private static TextLine PerformTextWrapping(IReadOnlyList<ShapedTextCharacters> textRuns, TextRange textRange,
-            double paragraphWidth, TextParagraphProperties paragraphProperties)
+        private static TextLine PerformTextWrapping(List<ShapedTextCharacters> textRuns, TextRange textRange,
+            double paragraphWidth, TextParagraphProperties paragraphProperties, TextLineBreak currentLineBreak)
         {
             var availableWidth = paragraphWidth;
             var currentWidth = 0.0;
@@ -388,8 +400,22 @@ namespace Avalonia.Media.TextFormatting
                     var textLineMetrics = TextLineMetrics.Create(splitResult.First,
                         new TextRange(textRange.Start, currentLength), paragraphWidth, paragraphProperties);
 
-                    var lineBreak = splitResult.Second != null && splitResult.Second.Count > 0 ?
-                        new TextLineBreak(splitResult.Second) :
+                    var remainingCharacters = splitResult.Second;
+
+                    if (currentLineBreak?.RemainingCharacters != null)
+                    {
+                        if (remainingCharacters != null)
+                        {
+                            remainingCharacters.AddRange(currentLineBreak.RemainingCharacters);
+                        }
+                        else
+                        {
+                            remainingCharacters = new List<ShapedTextCharacters>(currentLineBreak.RemainingCharacters);
+                        }
+                    }
+
+                    var lineBreak = remainingCharacters != null && remainingCharacters.Count > 0 ?
+                        new TextLineBreak(remainingCharacters) :
                         null;
 
                     return new TextLineImpl(splitResult.First, textLineMetrics, lineBreak);
@@ -403,7 +429,10 @@ namespace Avalonia.Media.TextFormatting
             }
 
             return new TextLineImpl(textRuns,
-                TextLineMetrics.Create(textRuns, textRange, paragraphWidth, paragraphProperties));
+                TextLineMetrics.Create(textRuns, textRange, paragraphWidth, paragraphProperties),
+                currentLineBreak?.RemainingCharacters != null ?
+                    new TextLineBreak(currentLineBreak.RemainingCharacters) :
+                    null);
         }
 
         /// <summary>
@@ -434,7 +463,7 @@ namespace Avalonia.Media.TextFormatting
 
         internal readonly struct SplitTextRunsResult
         {
-            public SplitTextRunsResult(IReadOnlyList<ShapedTextCharacters> first, IReadOnlyList<ShapedTextCharacters> second)
+            public SplitTextRunsResult(List<ShapedTextCharacters> first, List<ShapedTextCharacters> second)
             {
                 First = first;
 
@@ -447,7 +476,7 @@ namespace Avalonia.Media.TextFormatting
             /// <value>
             /// The first text runs.
             /// </value>
-            public IReadOnlyList<ShapedTextCharacters> First { get; }
+            public List<ShapedTextCharacters> First { get; }
 
             /// <summary>
             /// Gets the second text runs.
@@ -455,7 +484,7 @@ namespace Avalonia.Media.TextFormatting
             /// <value>
             /// The second text runs.
             /// </value>
-            public IReadOnlyList<ShapedTextCharacters> Second { get; }
+            public List<ShapedTextCharacters> Second { get; }
         }
 
         private struct TextRunEnumerator

src/Avalonia.Visuals/Media/TextFormatting/TextLayout.cs

@@ -183,7 +183,10 @@ namespace Avalonia.Media.TextFormatting
             var glyphRun = TextShaper.Current.ShapeText(new ReadOnlySlice<char>(s_empty, startingIndex, 1),
                 properties.Typeface, properties.FontRenderingEmSize, properties.CultureInfo);
 
-            var textRuns = new[] { new ShapedTextCharacters(glyphRun, _paragraphProperties.DefaultTextRunProperties) };
+            var textRuns = new List<ShapedTextCharacters>
+            {
+                new ShapedTextCharacters(glyphRun, _paragraphProperties.DefaultTextRunProperties)
+            };
 
             return new TextLineImpl(textRuns,
                 TextLineMetrics.Create(textRuns, new TextRange(startingIndex, 1), MaxWidth, _paragraphProperties));

src/Avalonia.Visuals/Media/TextFormatting/TextLineImpl.cs

@@ -6,9 +6,9 @@ namespace Avalonia.Media.TextFormatting
 {
     internal class TextLineImpl : TextLine
     {
-        private readonly IReadOnlyList<ShapedTextCharacters> _textRuns;
+        private readonly List<ShapedTextCharacters> _textRuns;
 
-        public TextLineImpl(IReadOnlyList<ShapedTextCharacters> textRuns, TextLineMetrics lineMetrics,
+        public TextLineImpl(List<ShapedTextCharacters> textRuns, TextLineMetrics lineMetrics,
             TextLineBreak lineBreak = null, bool hasCollapsed = false)
         {
             _textRuns = textRuns;

src/Avalonia.Visuals/Rendering/ICustomSimpleHitTest.cs

@@ -14,6 +14,17 @@ namespace Avalonia.Rendering
         bool HitTest(Point point);
     }
 
+    /// <summary>
+    /// Allows customization of hit-testing for all renderers.
+    /// </summary>
+    /// <remarks>
+    /// Note that this interface can only used to make a portion of a control non-hittable, it
+    /// cannot expand the hittable area of a control.
+    /// </remarks>
+    public interface ICustomHitTest : ICustomSimpleHitTest
+    {
+    }
+
     public static class CustomSimpleHitTestExtensions
     {
         public static bool HitTestCustom(this IVisual visual, Point point)

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

@@ -304,6 +304,12 @@ namespace Avalonia.Rendering.SceneGraph
                         clipped = !node.GeometryClip.FillContains(controlPoint.Value);
                     }
 
+                    if (!clipped && node.Visual is ICustomHitTest custom)
+                    {
+                        var controlPoint = _sceneRoot.Visual.TranslatePoint(_point, node.Visual);
+                        clipped = !custom.HitTest(controlPoint.Value);
+                    }
+
                     return !clipped;
                 }
 

src/Skia/Avalonia.Skia/TextShaperImpl.cs

@@ -123,10 +123,7 @@ namespace Avalonia.Skia
                 return;
             }
 
-            if (offsetBuffer == null)
-            {
-                offsetBuffer = new Vector[glyphPositions.Length];
-            }
+            offsetBuffer ??= new Vector[glyphPositions.Length];
 
             var offsetX = position.XOffset * textScale;
 
@@ -138,10 +135,7 @@ namespace Avalonia.Skia
         private static void SetAdvance(ReadOnlySpan<GlyphPosition> glyphPositions, int index, double textScale,
             ref double[] advanceBuffer)
         {
-            if (advanceBuffer == null)
-            {
-                advanceBuffer = new double[glyphPositions.Length];
-            }
+            advanceBuffer ??= new double[glyphPositions.Length];
 
             // Depends on direction of layout
             // advanceBuffer[index] = buffer.GlyphPositions[index].YAdvance * textScale;

tests/Avalonia.Controls.UnitTests/ListBoxTests_Multiple.cs

@@ -0,0 +1,126 @@
+using System.Linq;
+using Avalonia.Controls.Presenters;
+using Avalonia.Controls.Templates;
+using Avalonia.Input;
+using Avalonia.Styling;
+using Avalonia.UnitTests;
+using Avalonia.VisualTree;
+using Xunit;
+
+namespace Avalonia.Controls.UnitTests
+{
+    public class ListBoxTests_Multiple
+    {
+        [Fact]
+        public void Focusing_Item_With_Shift_And_Arrow_Key_Should_Add_To_Selection()
+        {
+            var target = new ListBox
+            {
+                Template = new FuncControlTemplate(CreateListBoxTemplate),
+                Items = new[] { "Foo", "Bar", "Baz " },
+                SelectionMode = SelectionMode.Multiple
+            };
+
+            ApplyTemplate(target);
+
+            target.SelectedItem = "Foo";
+
+            target.Presenter.Panel.Children[1].RaiseEvent(new GotFocusEventArgs
+            {
+                RoutedEvent = InputElement.GotFocusEvent,
+                NavigationMethod = NavigationMethod.Directional,
+                KeyModifiers = KeyModifiers.Shift
+            });
+
+            Assert.Equal(new[] { "Foo", "Bar" }, target.SelectedItems);
+        }
+
+        [Fact]
+        public void Focusing_Item_With_Ctrl_And_Arrow_Key_Should_Add_To_Selection()
+        {
+            var target = new ListBox
+            {
+                Template = new FuncControlTemplate(CreateListBoxTemplate),
+                Items = new[] { "Foo", "Bar", "Baz " },
+                SelectionMode = SelectionMode.Multiple
+            };
+
+            ApplyTemplate(target);
+
+            target.SelectedItem = "Foo";
+
+            target.Presenter.Panel.Children[1].RaiseEvent(new GotFocusEventArgs
+            {
+                RoutedEvent = InputElement.GotFocusEvent,
+                NavigationMethod = NavigationMethod.Directional,
+                KeyModifiers = KeyModifiers.Control
+            });
+
+            Assert.Equal(new[] { "Foo", "Bar" }, target.SelectedItems);
+        }
+
+        [Fact]
+        public void Focusing_Selected_Item_With_Ctrl_And_Arrow_Key_Should_Remove_From_Selection()
+        {
+            var target = new ListBox
+            {
+                Template = new FuncControlTemplate(CreateListBoxTemplate),
+                Items = new[] { "Foo", "Bar", "Baz " },
+                SelectionMode = SelectionMode.Multiple
+            };
+
+            ApplyTemplate(target);
+
+            target.SelectedItems.Add("Foo");
+            target.SelectedItems.Add("Bar");
+
+            target.Presenter.Panel.Children[0].RaiseEvent(new GotFocusEventArgs
+            {
+                RoutedEvent = InputElement.GotFocusEvent,
+                NavigationMethod = NavigationMethod.Directional,
+                KeyModifiers = KeyModifiers.Control
+            });
+
+            Assert.Equal(new[] { "Bar" }, target.SelectedItems);
+        }
+
+        private Control CreateListBoxTemplate(ITemplatedControl parent, INameScope scope)
+        {
+            return new ScrollViewer
+            {
+                Template = new FuncControlTemplate(CreateScrollViewerTemplate),
+                Content = new ItemsPresenter
+                {
+                    Name = "PART_ItemsPresenter",
+                    [~ItemsPresenter.ItemsProperty] = parent.GetObservable(ItemsControl.ItemsProperty).ToBinding(),
+                }.RegisterInNameScope(scope)
+            };
+        }
+
+        private Control CreateScrollViewerTemplate(ITemplatedControl parent, INameScope scope)
+        {
+            return new ScrollContentPresenter
+            {
+                Name = "PART_ContentPresenter",
+                [~ContentPresenter.ContentProperty] =
+                    parent.GetObservable(ContentControl.ContentProperty).ToBinding(),
+            }.RegisterInNameScope(scope);
+        }
+
+        private void ApplyTemplate(ListBox target)
+        {
+            // Apply the template to the ListBox itself.
+            target.ApplyTemplate();
+
+            // Then to its inner ScrollViewer.
+            var scrollViewer = (ScrollViewer)target.GetVisualChildren().Single();
+            scrollViewer.ApplyTemplate();
+
+            // Then make the ScrollViewer create its child.
+            ((ContentPresenter)scrollViewer.Presenter).UpdateChild();
+
+            // Now the ItemsPresenter should be reigstered, so apply its template.
+            target.Presenter.ApplyTemplate();
+        }
+    }
+}

tests/Avalonia.Controls.UnitTests/Platform/DefaultMenuInteractionHandlerTests.cs

@@ -124,6 +124,24 @@ namespace Avalonia.Controls.UnitTests.Platform
                 Assert.True(e.Handled);
             }
 
+            [Fact]
+            public void Click_On_TopLevel_Calls_MainMenu_Open()
+            {
+                var target = new DefaultMenuInteractionHandler(false);
+                var menu = new Mock<IMainMenu>();
+                menu.As<IMenuElement>();
+
+                var item = Mock.Of<IMenuItem>(x =>
+                    x.IsTopLevel == true &&
+                    x.HasSubMenu == true &&
+                    x.Parent == menu.Object);
+
+                var e = CreatePressed(item);
+
+                target.PointerPressed(item, e);
+                menu.Verify(x => x.Open());
+            }
+
             [Fact]
             public void Click_On_Open_TopLevel_Menu_Closes_Menu()
             {

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

@@ -14,6 +14,7 @@ using Avalonia.UnitTests;
 using Avalonia.VisualTree;
 using Xunit;
 using Avalonia.Input;
+using Avalonia.Rendering;
 
 namespace Avalonia.Controls.UnitTests.Primitives
 {
@@ -349,52 +350,48 @@ namespace Avalonia.Controls.UnitTests.Primitives
         }
 
         [Fact]
-        public void StaysOpen_False_Should_Not_Handle_Closing_Click()
+        public void OverlayDismissEventPassThrough_Should_Pass_Event_To_Window_Contents()
         {
             using (CreateServices())
             {
-                var window = PreparedWindow();
+                var renderer = new Mock<IRenderer>();
+                var platform = AvaloniaLocator.Current.GetService<IWindowingPlatform>();
+                var windowImpl = Mock.Get(platform.CreateWindow());
+                windowImpl.Setup(x => x.CreateRenderer(It.IsAny<IRenderRoot>())).Returns(renderer.Object);
+
+                var window = new Window(windowImpl.Object);
+                window.ApplyTemplate();
+
                 var target = new Popup() 
                 { 
                     PlacementTarget = window ,
-                    StaysOpen = false,
+                    IsLightDismissEnabled = true,
+                    OverlayDismissEventPassThrough = true,
                 };
 
-                target.Open();
-
-                var e = CreatePointerPressedEventArgs(window);
-                window.RaiseEvent(e);
+                var raised = 0;
+                var border = new Border();
+                window.Content = border;
 
-                Assert.False(e.Handled);
-            }
-        }
+                renderer.Setup(x =>
+                    x.HitTestFirst(new Point(10, 15), window, It.IsAny<Func<IVisual, bool>>()))
+                    .Returns(border);
 
-        [Fact]
-        public void Should_Pass_Closing_Click_To_Closed_Event()
-        {
-            using (CreateServices())
-            {
-                var window = PreparedWindow();
-                var target = new Popup()
+                border.PointerPressed += (s, e) =>
                 {
-                    PlacementTarget = window,
-                    StaysOpen = false,
+                    Assert.Same(border, e.Source);
+                    ++raised;
                 };
 
                 target.Open();
+                Assert.True(target.IsOpen);
 
-                var press = CreatePointerPressedEventArgs(window);
-                var raised = 0;
-
-                target.Closed += (s, e) =>
-                {
-                    Assert.Same(press, e.CloseEvent);
-                    ++raised;
-                };
-
-                window.RaiseEvent(press);
+                var e = CreatePointerPressedEventArgs(window, new Point(10, 15));
+                var overlay = LightDismissOverlayLayer.GetLightDismissOverlayLayer(window);
+                overlay.RaiseEvent(e);
 
                 Assert.Equal(1, raised);
+                Assert.False(target.IsOpen);
             }
         }
 
@@ -410,14 +407,14 @@ namespace Avalonia.Controls.UnitTests.Primitives
                     })));
         }
 
-        private PointerPressedEventArgs CreatePointerPressedEventArgs(Window source)
+        private PointerPressedEventArgs CreatePointerPressedEventArgs(Window source, Point p)
         {
             var pointer = new Pointer(Pointer.GetNextFreeId(), PointerType.Mouse, true);
             return new PointerPressedEventArgs(
                 source,
                 pointer,
                 source,
-                default,
+                p,
                 0,
                 new PointerPointProperties(RawInputModifiers.None, PointerUpdateKind.LeftButtonPressed),
                 KeyModifiers.None);

tests/Avalonia.Controls.UnitTests/Utils/SelectedItemsSyncTests.cs

@@ -208,6 +208,20 @@ namespace Avalonia.Controls.UnitTests.Utils
                 target.SetItems(new[] { "foo", "bar", "baz" }));
         }
 
+        [Fact]
+        public void Selected_Items_Can_Be_Set_Before_SelectionModel_Source()
+        {
+            var model = new SelectionModel();
+            var target = new SelectedItemsSync(model);
+            var items = new AvaloniaList<string> { "foo", "bar", "baz" };
+            var selectedItems = new AvaloniaList<string> { "bar" };
+
+            target.SetItems(selectedItems);
+            model.Source = items;
+
+            Assert.Equal(new IndexPath(1), model.SelectedIndex);
+        }
+
         private static SelectedItemsSync CreateTarget(
             IEnumerable<string> items = null)
         {

tests/Avalonia.UnitTests/MockWindowingPlatform.cs

@@ -3,6 +3,7 @@ using Avalonia.Controls.Primitives.PopupPositioning;
 using Avalonia.Input;
 using Moq;
 using Avalonia.Platform;
+using Avalonia.Rendering;
 
 namespace Avalonia.UnitTests
 {