Fix button flyout toggle

Expose OverlayDismissEventPassThrough on FlyoutBase

src/Avalonia.Controls/Button.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics;
 using System.Linq;
 using System.Windows.Input;
 using Avalonia.Automation.Peers;
@@ -281,24 +282,29 @@ namespace Avalonia.Controls
         /// <inheritdoc/>
         protected override void OnKeyDown(KeyEventArgs e)
         {
-            if (e.Key == Key.Enter)
+            switch (e.Key)
             {
-                OnClick();
-                e.Handled = true;
-            }
-            else if (e.Key == Key.Space)
-            {
-                if (ClickMode == ClickMode.Press)
-                {
+                case Key.Enter:
                     OnClick();
+                    e.Handled = true;
+                    break;
+
+                case Key.Space:
+                {
+                    if (ClickMode == ClickMode.Press)
+                    {
+                        OnClick();
+                    }
+
+                    IsPressed = true;
+                    e.Handled = true;
+                    break;
                 }
-                IsPressed = true;
-                e.Handled = true;
-            }
-            else if (e.Key == Key.Escape && Flyout != null)
-            {
-                // If Flyout doesn't have focusable content, close the flyout here
-                Flyout.Hide();
+
+                case Key.Escape when Flyout != null:
+                    // If Flyout doesn't have focusable content, close the flyout here
+                    CloseFlyout();
+                    break;
             }
 
             base.OnKeyDown(e);
@@ -327,7 +333,14 @@ namespace Avalonia.Controls
         {
             if (IsEffectivelyEnabled)
             {
-                OpenFlyout();
+                if (_isFlyoutOpen)
+                {
+                    CloseFlyout();
+                }
+                else
+                {
+                    OpenFlyout();
+                }
 
                 var e = new RoutedEventArgs(ClickEvent);
                 RaiseEvent(e);
@@ -348,6 +361,14 @@ namespace Avalonia.Controls
             Flyout?.ShowAt(this);
         }
 
+        /// <summary>
+        /// Closes the button's flyout.
+        /// </summary>
+        protected virtual void CloseFlyout()
+        {
+            Flyout?.Hide();
+        }
+
         /// <summary>
         /// Invoked when the button's flyout is opened.
         /// </summary>
@@ -494,8 +515,7 @@ namespace Avalonia.Controls
 
                 // If flyout is changed while one is already open, make sure we 
                 // close the old one first
-                if (oldFlyout != null &&
-                    oldFlyout.IsOpen)
+                if (oldFlyout != null && oldFlyout.IsOpen)
                 {
                     oldFlyout.Hide();
                 }

src/Avalonia.Controls/Flyouts/FlyoutBase.cs

@@ -12,11 +12,6 @@ namespace Avalonia.Controls.Primitives
 {
     public abstract class FlyoutBase : AvaloniaObject, IPopupHostProvider
     {
-        static FlyoutBase()
-        {
-            Control.ContextFlyoutProperty.Changed.Subscribe(OnContextFlyoutPropertyChanged);
-        }
-
         /// <summary>
         /// Defines the <see cref="IsOpen"/> property
         /// </summary>
@@ -49,6 +44,12 @@ namespace Avalonia.Controls.Primitives
         public static readonly AttachedProperty<FlyoutBase?> AttachedFlyoutProperty =
             AvaloniaProperty.RegisterAttached<FlyoutBase, Control, FlyoutBase?>("AttachedFlyout", null);
 
+        /// <summary>
+        /// Defines the OverlayDismissEventPassThrough property
+        /// </summary>
+        public static readonly StyledProperty<bool> OverlayDismissEventPassThroughProperty =
+            Popup.OverlayDismissEventPassThroughProperty.AddOwner<FlyoutBase>();
+
         private readonly Lazy<Popup> _popupLazy;
         private bool _isOpen;
         private Control? _target;
@@ -58,6 +59,12 @@ namespace Avalonia.Controls.Primitives
         private IDisposable? _transientDisposable;
         private Action<IPopupHost?>? _popupHostChangedHandler;
 
+        static FlyoutBase()
+        {
+            OverlayDismissEventPassThroughProperty.OverrideDefaultValue<FlyoutBase>(true);
+            Control.ContextFlyoutProperty.Changed.Subscribe(OnContextFlyoutPropertyChanged);
+        }
+
         public FlyoutBase()
         {
             _popupLazy = new Lazy<Popup>(() => CreatePopup());
@@ -101,6 +108,21 @@ namespace Avalonia.Controls.Primitives
             private set => SetAndRaise(TargetProperty, ref _target, value);
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether the event that closes the flyout is passed
+        /// through to the parent window.
+        /// </summary>
+        /// <remarks>
+        /// Clicks outside the the flyout cause the flyout to close. When <see cref="OverlayDismissEventPassThrough"/> is set to
+        /// false, these clicks will be handled by the flyout 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);
+        }
+
         IPopupHost? IPopupHostProvider.PopupHost => Popup?.Host;
 
         event Action<IPopupHost?>? IPopupHostProvider.PopupHostChanged 
@@ -175,6 +197,8 @@ namespace Avalonia.Controls.Primitives
 
             IsOpen = false;
             Popup.IsOpen = false;
+            Popup.OverlayInputPassThroughElement = null;
+
             ((ISetLogicalParent)Popup).SetParent(null);
             
             // Ensure this isn't active
@@ -231,6 +255,9 @@ namespace Avalonia.Controls.Primitives
                 Popup.Child = CreatePresenter();
             }
 
+            Popup.OverlayInputPassThroughElement = placementTarget;
+            Popup.OverlayDismissEventPassThrough = OverlayDismissEventPassThrough;
+
             if (CancelOpening())
             {
                 return false;
@@ -356,10 +383,11 @@ namespace Avalonia.Controls.Primitives
 
         private Popup CreatePopup()
         {
-            var popup = new Popup();
-            popup.WindowManagerAddShadowHint = false;
-            popup.IsLightDismissEnabled = true;
-            popup.OverlayDismissEventPassThrough = true;
+            var popup = new Popup
+            {
+                WindowManagerAddShadowHint = false,
+                IsLightDismissEnabled = true
+            };
 
             popup.Opened += OnPopupOpened;
             popup.Closed += OnPopupClosed;
@@ -372,7 +400,7 @@ namespace Avalonia.Controls.Primitives
         {
             IsOpen = true;
 
-            _popupHostChangedHandler?.Invoke(Popup!.Host);
+            _popupHostChangedHandler?.Invoke(Popup.Host);
         }
 
         private void OnPopupClosing(object? sender, CancelEventArgs e)

src/Avalonia.Controls/Primitives/Popup.cs

@@ -501,7 +501,7 @@ namespace Avalonia.Controls.Primitives
                 if (dismissLayer != null)
                 {
                     dismissLayer.IsVisible = true;
-                    dismissLayer.InputPassThroughElement = _overlayInputPassThroughElement;
+                    dismissLayer.InputPassThroughElement = OverlayInputPassThroughElement;
                     
                     Disposable.Create(() =>
                     {