I recently updated Firefox and the onmouseover effects have stopped working. This happens in Firefox 7.0.1 under OS X Lion. For example, if I move the mouse onto the "Search Improvements...." thread title, the page navigation UI should appear but doesn't. This happens on all XF sites I've tried including here and seems to be affecting older releases of XF as well (happens on a test site I have with 1.02). I've also disabled all Firefox addons which hasn't helped.