what is this

Well Hi guys i feel stupid but what is the button between my drivers window and rear drivers side window buttons? iv hit it and i didn't see anything... please help!:dunno:

Section I, (Or the stuff that you need to know) Manuals (Found and shared by BBoyvek, whored out by df). BMW Manuals This one went missing... Owners manual download at the bottom of this first posting That which is interchangable, and that which isn't. Common Issues aka "Things your car...