Firefox drop-down menus problem

[Default User <xyzzyx@sbcglobal.net>]

Running Debian stable, with Foxfire 1.04.  In Firefox, there is a
problem with the drop-down menus. Unhighlighted items show as black text
against a grey background (as expected). But items highlighted by moving
the mouse cursor over them show as white text on white background (thus
unreadable)! Yet clicking the menu items works as normal. 

This does not seem to happen for any other program, and does not occur
in Icewseasel (Etch).  Has anyone else experienced this?  If so, is
there a solution?