Driver's side window loose

I have power windows. The window on the drivers side has become detached from what ever holds it to the motor works. The motor is fine. If I pull the glass up by hand to about 2 or three inches from the top of the window frame, the motor track will raise it up and hold it firmly in place. If I attempt to lower the window, it will go down 2 or 3 inches and then free fall the rest of the way. What and how is the window held to the equipment that holds it in place.