<!DOCTYPE HTML> <title>Testcase for hypothetical box calculation for position:fixed inside -moz-transform</title> <style type="text/css"> html, body { margin: 0; padding: 0; } </style> <div style="-moz-transform: translate(10px,10px); width:0"> <div style="height: 20px"></div> <div style="position: fixed; height: 10px; width: 10px; background: blue"></div> </div>