<!DOCTYPE HTML>
<html reftest-async-scroll>
<body>
  <div reftest-displayport-x="0" reftest-displayport-y="0"
       reftest-displayport-w="800" reftest-displayport-h="1000"
       style="overflow: scroll; position: absolute; top: 0; left: 0; bottom: 0; right: 0; z-index: 3;">
    <div style="background: purple; height: 50px;"></div>
  </div>
  <div style="width: 50px; height: 50px; background: url('solidblue.png'); position: absolute; top: 100px; left: 50px; z-index: 4;">
  </div>
</body>
</html>