what holds the remote mirror control in place?

I seem to have misplaced something for my remote mirror control. I have the bezel for the outside, but what holds in from the inside of the door? If that makes sense. O forgot to take a pic and am not near the car right now. Basically if I put it in the hole and put the bezel on o can still pull it away from the door. Any idea what holds it or where to get one??