My Exposé and Spaces suddenly become sluggish since last night. It had been very smooth since my installation of Snow Leopard but now it is lagging like hell. It seems the problem is spreading as well - Now it even lags when I am scrolling in a stack, and this problem didn't appear last night. I have rebooted, killall'd Dock, removed com.apple.Dock.plist, but still no luck. Can anybody help me please??