From 4ad23738fd0ac7925ec71f9157a298fd32044971 Mon Sep 17 00:00:00 2001
From: Felix Trautmann <felix@trautmann-it.de>
Date: Wed, 26 Oct 2022 14:33:29 +0200
Subject: [PATCH] removing ThemeChangedEvent from ClientAreaBorder and TitleBar
 if the parent window is closing

---
 src/Wpf.Ui/Controls/ClientAreaBorder.cs | 13 +++++++++++--
 src/Wpf.Ui/Controls/TitleBar.cs         |  2 +-
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/Wpf.Ui/Controls/ClientAreaBorder.cs b/src/Wpf.Ui/Controls/ClientAreaBorder.cs
index d15431069..ec8c53bc6 100644
--- a/src/Wpf.Ui/Controls/ClientAreaBorder.cs
+++ b/src/Wpf.Ui/Controls/ClientAreaBorder.cs
@@ -6,12 +6,14 @@
 #nullable enable
 
 using System;
+using System.ComponentModel;
 using System.Windows;
 using System.Windows.Media;
 using System.Windows.Shell;
 using Wpf.Ui.Appearance;
 using Wpf.Ui.Controls.Interfaces;
 using Wpf.Ui.Dpi;
+using Wpf.Ui.Interop;
 using Size = System.Windows.Size;
 
 namespace Wpf.Ui.Controls;
@@ -78,7 +80,7 @@ public Thickness PaddedBorderThickness
     /// <summary>
     /// If you use a <see cref="WindowChrome"/> to extend the client area of a window to the non-client area, you need to handle the edge margin issue when the window is maximized.
     /// Use this property to get the correct margin value when the window is maximized, so that when the window is maximized, the client area can completely cover the screen client area by no less than a single pixel at any DPI.
-    /// The<see cref="Interop.User32.GetSystemMetrics"/> method cannot obtain this value directly.
+    /// The<see cref="User32.GetSystemMetrics"/> method cannot obtain this value directly.
     /// </summary>
     public Thickness WindowChromeNonClientFrameThickness => _windowChromeNonClientFrameThickness ??= new Thickness(
         ResizeFrameBorderThickness.Left + PaddedBorderThickness.Left,
@@ -110,6 +112,7 @@ protected override void OnVisualParentChanged(DependencyObject oldParent)
         if (_oldWindow is { } oldWindow)
         {
             oldWindow.StateChanged -= OnWindowStateChanged;
+            oldWindow.Closing -= OnWindowClosing;
         }
 
         var newWindow = (Window?)Window.GetWindow(this);
@@ -118,13 +121,19 @@ protected override void OnVisualParentChanged(DependencyObject oldParent)
         {
             newWindow.StateChanged -= OnWindowStateChanged; // Unsafe
             newWindow.StateChanged += OnWindowStateChanged;
+            newWindow.Closing += OnWindowClosing;
         }
 
         _oldWindow = newWindow;
 
         ApplyDefaultWindowBorder();
     }
-
+    private void OnWindowClosing(object? sender, CancelEventArgs e)
+    {
+        Appearance.Theme.Changed -= OnThemeChanged;
+        if (_oldWindow != null)
+            _oldWindow.Closing -= OnWindowClosing;
+    }
     private void OnWindowStateChanged(object? sender, EventArgs e)
     {
         if (sender is not Window window)
diff --git a/src/Wpf.Ui/Controls/TitleBar.cs b/src/Wpf.Ui/Controls/TitleBar.cs
index ca9ad8e60..de058a413 100644
--- a/src/Wpf.Ui/Controls/TitleBar.cs
+++ b/src/Wpf.Ui/Controls/TitleBar.cs
@@ -450,7 +450,7 @@ private void CloseWindow()
 
             return;
         }
-
+        Appearance.Theme.Changed -= OnThemeChanged;
         ParentWindow.Close();
     }