diff --git a/glue_solara/app.py b/glue_solara/app.py
index e62e4df..a4f2ff5 100644
--- a/glue_solara/app.py
+++ b/glue_solara/app.py
@@ -309,7 +309,7 @@ def on_viewer_close(index: int):
         mdi_layouts.set(new_mdi_layouts)
 
         # Remove the viewer from grid layouts
-        new_grid_layout = grid_layout.value
+        new_grid_layout = copy.deepcopy(grid_layout.value)
         new_grid_layout.pop(index)
         # We need to update the indices of the viewers in the grid layout, otherwise we get placeholder elements
         for layout in new_grid_layout: