diff --git a/ViewModels/MainViewModel.cs b/ViewModels/MainViewModel.cs
index 5817f58..76fbefc 100644
--- a/ViewModels/MainViewModel.cs
+++ b/ViewModels/MainViewModel.cs
@@ -105,6 +105,13 @@ public partial class MainViewModel : ViewModelBase
 
     private void OnSelectedElementPropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
     {
+        // ⛔ Safety net for EVERY property control: a static layer's appearance is baked into the
+        // scene cache keyed on element identity, so changing a property without invalidating the
+        // bake repaints nothing — the control looks dead. The Background toggle was the first case
+        // found (2026-11-01); the cause is generic, so the cure is here rather than one handler per
+        // property. Cheap: the bake is recomputed on demand, once.
+        if (StagedScene != null) _sceneGraph.InvalidateBake(StagedScene);
+
         if (e.PropertyName == nameof(SceneElement.UseDefaultBackground))
         {
             // ⛔ Turning the default back ON has to RE-STAMP the shipped art. Browse… writes the
@@ -122,8 +129,12 @@ public partial class MainViewModel : ViewModelBase
                 }
             }
 
-            if (StagedScene != null) _sceneGraph.InvalidateBake(StagedScene);
+            // Both surfaces: UpdateBackgroundImage drives the preview's lower layer,
+            // UpdateActiveBackground drives ActiveBackgroundImage (the art the preview draws above
+            // it). Refreshing only the first is why the thumbnails changed while the preview did
+            // not (creator report, 2026-11-01).
             UpdateBackgroundImage();
+            UpdateActiveBackground();
             RefreshSnapshotsAsync();
             ScheduleSave();
         }