x2 on zipping just an inch or so and then inserting into the channel. that's the only way i can keep mine from popping out.

are we still talking about windows???

 

Ok dudes, it's hard to tell from the picture, but that looks EXACTLY like mine BEFORE I put the window on the right way. Like some of the guys have said, the plastic piece tucks back into the frame, it doesn't just get sandwiched between the frame and the door so you need to just start the zipper at the top and tuck that bastard back into the frame.

Put another way: if you were looking at a correctly installed rear window from the front of the vehicle, you would be looking at the bottom of a "U" with one side of the U tucked back into the door frame and the other side of the U as the outward facing rear window.

Put still another way: if you remove your back doors, the rear windows should stay perfectly tucked into the frame, and there should be no flapping from the front part of the rear window because the plastic piece is shoved back into the frame.

Sorry if that description is bad or if I'm repeating what everyone already knows, but I had my JK for two years before I discovered the "right" way to install the rear windows.

 

I have the exact same problem (driver side only). It is caused by the stitching ... the sewing pattern is a little off and thicker as a result

 

I've never had a problem with the sides. I've always zipped all the way, tuck vertical channel, tuck bottom channel, then go and fasten all the velcro. No problems ever. The rear window is a complete PITA tho

 

The only way I got mine to work correctly was by zipping the zipper about an inch, then tucking the vertical plastic part in STARTING AT THE TOP and working down. If I started from the bottom, the window would always end up too high and curve out like the pics.