diff --git a/examples/notebooks/image_widget_test.ipynb b/examples/notebooks/image_widget_test.ipynb
index 6602dfce9..90747757c 100644
--- a/examples/notebooks/image_widget_test.ipynb
+++ b/examples/notebooks/image_widget_test.ipynb
@@ -441,7 +441,9 @@
    "id": "870627ef-09d8-44e4-8952-aedb702d1526",
    "metadata": {},
    "outputs": [],
-   "source": []
+   "source": [
+    "notebook_finished()"
+   ]
   }
  ],
  "metadata": {