<!DOCTYPE html>
<html>
<head>
<title>Stretchy mover</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
</head>
<body>
<!-- See bug 687807 -->
<math display=block>
<mrow>
<mspace depth="5em"/>
<mover>
<mo stretchy="true">↑</mo>
<mn>B</mn>
</mover>
</mrow>
</math>
</body>
</html>
