Sticking window in a '93 Olds Cutlass Ciera

Hey, just acquired a '93 Cutlass Ciera station wagon.

The problem with the passenger front window is this: it’ll go down, all the way. Coming up, though, It’ll only go up about 2" from wherever it was last. then, if you wait 5-10 minutes, it’ll go up another 2". So, you can eventually get the window all the way up, but it takes 30-60 minutes.

I pulled the door panel off–the glass is not out-of-track. I think the problem might be the notched rubber belt that the motor works on to move the window up/down: I suspect it’s binding somehow, and needs 5-10 minutes to distribute the tension from the motor along the belt, or something.

I’m asking here because I suspect (hope?) that this is a well-known GM problem, with an equally well-known fix.