<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<style>
/* use attribute selector instead of the .class shorthand to work around bug 379178 */
*[class="fixed"] { position: fixed; }
math, mtable, mtr { position: inherit; }
</style>
</head>
<body>
<div class="fixed">
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mtable>
<mtr class="fixed">
<mtd><mi>x</mi></mtd>
</mtr>
<mtr>
<mtd><mi>y</mi></mtd>
</mtr>
</mtable>
</math>
</div>
</body>
</html>