Fix: Properly dispose of column content to prevent memory leaks (#17548)

Co-authored-by: seer-by-sentry[bot] <157164994+seer-by-sentry[bot]@users.noreply.github.com>

Author: seer-by-sentry[bot]

src/Files.App/Views/Layouts/ColumnsLayoutPage.xaml.cs

@@ -162,9 +162,10 @@ public override void Dispose()
 		{
 			base.Dispose();
 
-			var columnHostItems = ColumnHost.Items.OfType<BladeItem>().Select(blade => blade.Content as Frame);
+			var columnHostItems = ColumnHost.Items.OfType<BladeItem>().Select(blade => blade.Content as Frame).ToList();
 			foreach (var frame in columnHostItems)
 			{
+				// Unsubscribe all event handlers BEFORE disposing to prevent race conditions
 				if (frame?.Content is ColumnShellPage shPage)
 				{
 					shPage.ContentChanged -= ColumnViewBrowser_ContentChanged;
@@ -179,6 +180,7 @@ public override void Dispose()
 				if (frame?.Content is UIElement element)
 					element.GotFocus -= ColumnViewBrowser_GotFocus;
 
+				// Dispose content AFTER unsubscribing all event handlers
 				if (frame?.Content is IDisposable disposable)
 					disposable.Dispose();
 			}
@@ -207,9 +209,7 @@ public void DismissOtherBlades(int index)
 					{
 						var frame = ColumnHost.ActiveBlades[index + 1].Content as Frame;
 
-						if (frame?.Content is IDisposable disposableContent)
-							disposableContent.Dispose();
-
+						// Unsubscribe event handlers BEFORE disposing to prevent race conditions
 						if ((frame?.Content as ColumnShellPage)?.SlimContentPage is ColumnLayoutPage columnLayout)
 						{
 							columnLayout.ItemInvoked -= ColumnViewBase_ItemInvoked;
@@ -220,6 +220,10 @@ public void DismissOtherBlades(int index)
 						(frame?.Content as UIElement).GotFocus -= ColumnViewBrowser_GotFocus;
 						(frame?.Content as ColumnShellPage).ContentChanged -= ColumnViewBrowser_ContentChanged;
 
+						// Dispose content AFTER unsubscribing event handlers
+						if (frame?.Content is IDisposable disposableContent)
+							disposableContent.Dispose();
+
 						ColumnHost.Items.RemoveAt(index + 1);
 						ColumnHost.ActiveBlades.RemoveAt(index + 1);
 					}