Comment 5 for bug 210369

I use CCSM and I have this problem too. Well, the menus and tooltips are not invisible, they just hide behind everything else, including the active window. Even my screensaver appears only in the background. I can still use the application menu if I minimize all other windows, for example.
I can resolve this by switching visual effects to 'none' and back to 'extra'. I also tried switching one plug-in off at a time and testing whether the menus work, but that doesn't help: apparently, not one plug-in is responsible for this.
I don't know how to reproduce it exactly, sometimes the problem just appears.