I somehow managed to lock all vertex (edge/face also) movement to the XY-plane. Whenever I try to move something, it just behaves as if I pressed Shift-Z and if I try to restrict it to Z-axis, it shows the distance in the top right, but nothign moves. I have no idea how this happened, nad now I cannot edit my object...
So my question is: how can I turn this off? and how can I turn it on later (since this is a really cool and it would be cool do this on purpose)?
I tried duplicating the object, the lock stays. It also stays if I save and reopen the file. I tried to rotatae the object and edit it afterwards, it locks to local axis, and does the same thing.
EDIT: added the screenshot