Mac Screen Invert Shortcut Broken?

Anyone out there with an older mac (not the new intel ones): try to invert your screen with the old handy-dandy CMD-OPT-CTRL-8. It doesn't work on mine anymore after the latest system update. I can do it from System Preferences, but that's a serious pain in the ass compared to the keyboard shortcut. Ho hum.

UPDATE [2006-04-08T09:46:02]: Well, maybe Macs are starting to behave more like a Windows PC. None of the screen brightness keys or volume keys were working... then, after a shutdown and reboot, everything works again.