On a day-to-day basis I run: Adobe PS, INDD, and AI, Microsoft Entourage, Firefox and iTunes. Just recently, after an upgrade to Leopard, I added Things and Simplify Media to the list. The problem that happens before (on Tiger) and now (on Leopard) is command+tab switching stops functioning and Expose hot corners and shortcuts stop working. I'm pretty sure this isn't a Finder crash because before, on Tiger, I could quit+restart Firefox and everything would be back to normal. Almost as if some shortcut had causes the system to act differently or there was some app dissonance? But now, with Leopard, nothing I quit will cause these two features to act properly until I do a restart. Both features (command+tab switching and expose) are very necessary for my work flow. I have checked SysPref to make sure keyboard shortcuts are default and Univeral Access to make sure assisted devices is turned off. Any help on this would be much appreciated!