<!DOCTYPE HTML>
<html style="overflow:hidden" class="reftest-wait"
      reftest-displayport-w="800" reftest-displayport-h="2000">
<body>
<div id="x" style="position:absolute; width:400px; height:400px; background:red;">
You should not see any red
</div>
<script>
function doTest() {
  document.getElementById('x').style.visibility = 'hidden';
  document.documentElement.removeAttribute("class");
}
window.addEventListener("MozReftestInvalidate", doTest, false);
</script>
</body>
</html>