<!DOCTYPE HTML>
<html class="reftest-wait">
<head>
<style>
body {
  width: 1500px;
  overflow: hidden;
}
div#bottom {
  position: fixed;
  left: 0;
  top: 0;
  height: 200px;
  width: 200px;
  background: green;
}
</style>
</head>
<body>
<div id="bottom"></div>
<div style="width:600px; height:100px; background:pink;"></div>
<script>
document.documentElement.scrollLeft = 200;
function doTest() {
  document.documentElement.removeAttribute("class");
  document.documentElement.scrollLeft = 0;
}
window.addEventListener("MozReftestInvalidate", doTest, false);
</script>
</body>
</html>