layout: Use tiles_mut() in Workspace::clear_unmap_snapshot()

src/layout/workspace.rs

@@ -1644,15 +1644,13 @@ impl<W: LayoutElement> Workspace<W> {
     }
 
     pub fn clear_unmap_snapshot(&mut self, window: &W::Id) {
-        for col in &mut self.columns {
+        for tile in self.tiles_mut() {
-            for tile in &mut col.tiles {
             if tile.window().id() == window {
                 let _ = tile.take_unmap_snapshot();
                 return;
             }
         }
     }
-    }
 
     pub fn start_close_animation_for_window(
         &mut self,