Following the most recent update of Firefox, there was a change to the fonts/colors that made the mouse-over pop-up balloons unreadable. They're now showing up with a black background and black text font. The only comment thread I found suggested a change to the GTK3 font settings in Linux (I'm running Ubuntu 12.10 quantal). However, this seems like using a sledgehammer to drive a nail. Surely there is some option in firefox itself that allows the user to reset the background or text colors of mouse-over popup balloons?