diff --git a/docs/getting-started/demo/what-is-an-awkward-array.ipynb b/docs/getting-started/demo/what-is-an-awkward-array.ipynb
index ff45a79a8b..214d4a2945 100644
--- a/docs/getting-started/demo/what-is-an-awkward-array.ipynb
+++ b/docs/getting-started/demo/what-is-an-awkward-array.ipynb
@@ -1,5 +1,13 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "deletable": false,
+    "editable": false
+   },
+   "source": "<center>\n<button data-commandLinker-command=\"application:toggle-zen\" href=\"#\">Toggle fullscreen</i></button>\n</center>"
+  },
   {
    "cell_type": "markdown",
    "id": "53a4d322",