message: Hid overflow otherwise could scroll nested tab
  It would reveal the black background of the stack
diff: </style>
  </head>
  <body style="height:100%">
  - <div id="content" style="display: flex; height: 100%"></div>
  + <div id="content" style="display: flex; height: 100%; overflow: hidden;"></div>
  <script src="app.web.js"></script>
  </body>
  