Fix WindowCommand brushes when using Flyouts

MahApps.Metro/Behaviours/InternalCleanWindowGlueBehavior.cs

@@ -54,21 +54,8 @@ protected override void OnDetaching()
 
         void AssociatedMetroWindow_FlyoutsStatusChanged(object sender, RoutedEventArgs e)
         {
-            MetroWindow.FlyoutStatusChangedRoutedEventArgs args = e as MetroWindow.FlyoutStatusChangedRoutedEventArgs;
-            var flyout = args.ChangedFlyout;
-
-            if (flyout.Position == Position.Right || flyout.Position == Position.Top)
-            {
-                if (flyout.IsOpen)
-                {
-                    this.AssociatedMetroWindow.HandleFlyout(flyout, (Brush)this.AssociatedMetroWindow.FindResource("WhiteColorBrush"));
-                }
-                else
-                {
-                    this.SetWindowCommandButtonsToBlackBrush();
-                    AssociatedMetroWindow.WindowButtonCommands.SetResourceReference(Control.ForegroundProperty, "BlackColorBrush");
-                }
-            }
+            var flyouts = this.AssociatedMetroWindow.Flyouts.Items.Cast<Flyout>().ToList();
+            this.AssociatedMetroWindow.HandleWindowCommandsForFlyouts(flyouts, (Brush) this.AssociatedMetroWindow.FindResource("BlackColorBrush"));
         }
     }
 }

MahApps.Metro/Controls/Flyout.cs

@@ -126,13 +126,10 @@ public Flyout()
                         this.ChangeFlyoutTheme(accent, windowTheme.Item1);
                     }
                 }
-
-                ThemeManager.IsThemeChanged += this.ThemeManager_IsThemeChanged;
             };
-            this.Unloaded += (sender, args) => ThemeManager.IsThemeChanged -= this.ThemeManager_IsThemeChanged;
         }
 
-        private void ChangeFlyoutTheme(Accent windowAccent, Theme windowTheme)
+        internal void ChangeFlyoutTheme(Accent windowAccent, Theme windowTheme)
         {
             // Beware: Über-dumb code ahead!
             switch (this.Theme)

MahApps.Metro/Controls/MetroWindow.cs

@@ -373,6 +373,27 @@ private void MetroWindow_Loaded(object sender, RoutedEventArgs e)
             {
                 this.Flyouts = new FlyoutsControl();
             }
+
+            ThemeManager.IsThemeChanged += ThemeManagerOnIsThemeChanged;
+            this.Unloaded += (o, args) => ThemeManager.IsThemeChanged -= ThemeManagerOnIsThemeChanged;
+        }
+
+        private void ThemeManagerOnIsThemeChanged(object sender, OnThemeChangedEventArgs e)
+        {
+            if (e.Accent != null)
+            {
+                var flyouts = this.Flyouts.Items.Cast<Flyout>().ToList();
+
+                if (!flyouts.Any())
+                    return;
+
+                foreach (Flyout flyout in flyouts)
+                {
+                    flyout.ChangeFlyoutTheme(e.Accent, e.Theme);
+                }
+
+                this.HandleWindowCommandsForFlyouts(flyouts);
+            }
         }
 
         static MetroWindow()
@@ -543,18 +564,7 @@ internal void HandleFlyoutStatusChange(Flyout flyout, IEnumerable<Flyout> visibl
                 WindowCommandsPresenter.SetValue(Panel.ZIndexProperty, this.ShowWindowCommandsOnTop ? zIndex : (zIndex > 0 ? zIndex - 1 : 0));
                 WindowButtonCommands.SetValue(Panel.ZIndexProperty, zIndex);
 
-                // We need to adapt the window commands to the theme of the flyout
-                // This only needs to be done for the accent and light theme, 
-                // the dark theme is the default one and will work out of the box
-                if (flyout.IsOpen)
-                {
-                    this.HandleFlyout(flyout);
-                }
-
-                else
-                {
-                    this.ResetAllWindowCommandsBrush();
-                }
+                this.HandleWindowCommandsForFlyouts(visibleFlyouts);
             }
 
             flyoutModal.Visibility = visibleFlyouts.Any(x => x.IsModal) ? Visibility.Visible : Visibility.Hidden;

MahApps.Metro/Controls/MetroWindowHelpers.cs

@@ -13,11 +13,32 @@ namespace MahApps.Metro.Controls
     /// </summary>
     internal static class MetroWindowHelpers
     {
-        public static void ChangeAllWindowCommandsBrush(this MetroWindow window, Brush brush)
+        /// <summary>
+        /// Adapts the WindowCommands to the theme of the first opened, topmost && && (top || right) flyout
+        /// </summary>
+        /// <param name="flyouts">All the flyouts! Or flyouts that fall into the category described in the summary.</param>
+        /// <param name="resetBrush">An optional brush to reset the window commands brush to.</param>
+        public static void HandleWindowCommandsForFlyouts(this MetroWindow window, IEnumerable<Flyout> flyouts, Brush resetBrush = null)
         {
-            window.ChangeWindowCommandButtonsBrush(brush);
+            var flyout = flyouts
+                .Where(x => x.IsOpen && (x.Position == Position.Right || x.Position == Position.Top))
+                .OrderByDescending(Panel.GetZIndex)
+                .FirstOrDefault();
 
-            window.WindowButtonCommands.SetValue(Control.ForegroundProperty, brush);
+            if (flyout != null)
+            {
+                window.UpdateWindowCommandsForFlyout(flyout);
+            }
+
+            else if(resetBrush == null)
+            {
+                window.ResetAllWindowCommandsBrush();
+            }
+
+            else
+            {
+                window.ChangeAllWindowCommandsBrush(resetBrush);
+            }
         }
 
         public static void ResetAllWindowCommandsBrush(this MetroWindow window)
@@ -27,25 +48,7 @@ public static void ResetAllWindowCommandsBrush(this MetroWindow window)
             window.WindowButtonCommands.ClearValue(Control.ForegroundProperty);
         }
 
-        public static void ChangeWindowCommandButtonsBrush(this MetroWindow window, string resourceName)
-        {
-            window.InvokeCommandButtons(x => x.SetResourceReference(Control.ForegroundProperty, resourceName));
-        }
-
-        public static void ChangeWindowCommandButtonsBrush(this MetroWindow window, Brush brush)
-        {
-            window.InvokeCommandButtons(x => x.SetValue(Control.ForegroundProperty, brush));
-        }
-
-        private static void InvokeCommandButtons(this MetroWindow window, Action<Button> action)
-        {
-            foreach (Button b in ((WindowCommands)window.WindowCommandsPresenter.Content).FindChildren<Button>())
-            {
-                action(b);
-            }
-        }
-
-        public static void HandleFlyout(this MetroWindow window, Flyout flyout, Brush darkThemeBrush = null)
+        public static void UpdateWindowCommandsForFlyout(this MetroWindow window, Flyout flyout)
         {
             Brush brush = null;
 
@@ -59,15 +62,36 @@ public static void HandleFlyout(this MetroWindow window, Flyout flyout, Brush da
                 brush = (Brush)ThemeManager.LightResource["BlackBrush"];
             }
 
-            else if(flyout.ActualTheme == Theme.Dark && darkThemeBrush != null)
+            else if (flyout.ActualTheme == Theme.Dark)
             {
-                brush = darkThemeBrush;
+                brush = (Brush)ThemeManager.DarkResource["BlackBrush"];
             }
 
-            if (brush != null)
+             window.ChangeAllWindowCommandsBrush(brush);
+        }
+        public static void ChangeWindowCommandButtonsBrush(this MetroWindow window, string brush)
+        {
+            window.InvokeCommandButtons(x => x.SetResourceReference(Control.ForegroundProperty, brush));
+        }
+
+        private static void ChangeWindowCommandButtonsBrush(this MetroWindow window, Brush brush)
+        {
+            window.InvokeCommandButtons(x => x.SetValue(Control.ForegroundProperty, brush));
+        }
+
+        private static void InvokeCommandButtons(this MetroWindow window, Action<Button> action)
+        {
+            foreach (Button b in ((WindowCommands)window.WindowCommandsPresenter.Content).FindChildren<Button>())
             {
-                window.ChangeAllWindowCommandsBrush(brush);
+                action(b);
             }
         }
+
+        private static void ChangeAllWindowCommandsBrush(this MetroWindow window, Brush brush)
+        {
+            window.ChangeWindowCommandButtonsBrush(brush);
+
+            window.WindowButtonCommands.SetValue(Control.ForegroundProperty, brush);
+        }
     }
 }