<html class="reftest-wait">
<head>
<script>

function boom()
{
  document.getElementById("M").style.width = "6em";
  document.documentElement.removeAttribute("class");
}

</script>

<body onload="setTimeout(boom, 30);">

<div style="position:absolute; top: 50px; left: 50px; border: 2px solid orange;">

  <select>
    <option id="M">M</option>
  </select>
 
  <br>
 
  <select style="width: 200%">
    <option style="visibility: collapse; overflow: auto; display: table-footer-group;">X</option>
  </select>
 
</div>

</body>
</html>