<!DOCTYPE html>
<link rel=author href="mailto:jarhar@chromium.org">
<link rel=help href="https://bugs.chromium.org/p/chromium/issues/detail?id=1267276">

<table>foo</table>
<details open=true>
  <dialog open=true>
    <table>
      <tr></tr>
    </table>
  </dialog>
</details>

<script>
  const dialog = document.querySelector('dialog');
  dialog.close();
  dialog.showModal();
  const cell = document.querySelector('tr').insertCell();
  document.querySelector('details').appendChild(cell);
  document.body.attachShadow({mode: 'closed'});
</script>