I recently upgrade my Ubuntu installation from 11.10 to 12.04.
Before the upgrade I was able to use three-finger tapping to bring up the grab-handles. Unfortunately, after the upgrade, that functionality is broken, since I cannot use the three-finger tap anymore.
Because the touchpad settings in ubuntu are somewhat limited, I don't really know what to do right now.
I hope someone can help me with that. I'll be glad to provide more info if needed.
Edit: The issue is not the gesture, but the binding of grab handles.
In CCSM, I cannot assign the middle-click to the grab-handle toggle.