Strange failure with Spaces? Over the course of my ownership of a MacBook Pro running Lion, I've had an extremely odd bug occur somewhat sporadically. It rarely occurs, but when it does, the following effects become apparent:


I can no longer switch spaces using trackpad gestures, but I can using keyboard shortcuts.
Dashboard becomes inaccessible without using Mission Control; only the main spaces can be moved through with the shortcut keys.
When moving between spaces, all easing is gone from the transition animations. The animation seems more like it was in Snow Leopard and prior.


I really have no idea what could possibly cause this, and even though it's only happened to me four or five times, it's quite annoying since I use Spaces a lot. The only way I've found to resolve the problem was restarting the entire OS. Has anyone else had this happen to them? If so, do you know of a fix?
I eventually managed to find the issue by poking around in console. I got the following error messages:

Dock: kCGErrorIllegalArgument: _CGSFindSharedWindow: WID 6963
Dock: kCGErrorIllegalArgument: CGSGetWindowTags: Invalid window 0x1b33
Dock: kCGErrorIllegalArgument: CGSGetWorkspaceWindowGroup
Dock: kCGErrorIllegalArgument: CGSGetWindowOwner
Dock: kCGErrorIllegalArgument: CGSGetWindowBounds
Dock: kCGErrorIllegalArgument: CGSSetWindowListSystemLevel: Failed
Dock: kCGErrorIllegalArgument: _CGSFindSharedWindow: WID 6963
Dock: kCGErrorIllegalArgument: CGSGetWindowTags: Invalid window 0x1b33
Dock: kCGErrorIllegalArgument: CGSGetWorkspaceWindowGroup
Dock: kCGErrorIllegalArgument: CGSGetWindowOwner
Dock: kCGErrorIllegalArgument: CGSGetWindowBounds


While I'm not positive what causes these, sure enough, restarting the Dock using killall Dock did the trick. Though I still have no idea what causes this in the first place, this is at least a fix for the rare problem.