<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" onload="setTimeout(boom, 30);" class="reftest-wait">

<script>
function boom() {
  var a = document.getElementById('a');
  var x = a.popupBoxObject;
  a.parentNode.removeChild(a);
  x.enableKeyboardNavigator(true);
  x.openPopup(null, "after_start", 0, 0, false, false);
  x.openPopupAtScreen(2, 2, false);
  x.showPopup(document.documentElement, a, -1, -1, "popup", "topleft", "topleft");
  x.hidePopup();
  document.documentElement.removeAttribute("class");
}

</script>

<menupopup id="a"/>

</window>
