I have an issue that's finally just frustrating enough to want to fix it. I use Exposé's hot corners on my Al MB. I also use an external monitor at my desk. When I unplug the monitor to disconnect the laptop from being "docked" (as it were), I find that I can't use hot corners anymore. If I restart the Finder, that doesn't fix the issue. If I go to Exposé preferences, and change a hot corner preference (e.g., what gets done when one goes to the upper right corner), then things get fixed. But I really don't want to go to Sys. Prefs. each time I change monitors. Is there any other solution?