I just upgraded to this (Leopard 10.5, FF 3.5.7), and the feature I used the most is now borked. Right-clicking an element and selecting "inspect element", or e

I just upgraded to this (Leopard 10.5, FF 3.5.7), and the feature I used the most is now borked. Right-clicking an element and selecting "inspect element", or expanding Firebug and expanding the nested child elements (clicking the arrow to expand the contents of the div > the form > the fieldset > the input) is now completely broken. Has anybody else had this happen? Any fixes you can recommend?