<!DOCTYPE html>
<html>
<head>
  <title>Testcase Bug 851514</title>
  <style>
  #parent {
    position: fixed;
    height: 30px;
    width: 30px;
    background: green;
    left: 70px;
    top: 70px;
  }
  #child {
    position: fixed;
    top: auto;
    left: auto;
    width: 10px;
    height: 10px;
    background: purple;
  }
  </style>
</head>
<body>
  <div id="parent">
    <div id="child"></div>
  </div>
  The purple block should be inside the green block.
</body>
</html>