What's broken on my window track?

Both my windows on my 2 door fall forward if not rolled up all the way. I can't figure out what is broken. Video below; I know there's a missing bolt there but that's not the problem.

c8U1jKZ-wMQ

if you can't see video click this link http://www.youtube.com/watch?v=c8U1jKZ-wMQ

I think I figured it out:

http://i121.photobucket.com/albums/o219/ernestmayhand/Caprice%20resto/907dabd2.jpg
Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_1 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8B117 Safari/6531.22.7

Yup. That's it!

I replaced those when I replaced the window channels/felts on my 89.

Had the same problem.

Yes indeed. Window guides. Get these from your GM dealer, the Autozone ones don't work well. As a bonus, they're actually CHEAPER through GM.

Get these from your GM dealer, the Autozone ones don't work well. As a bonus, they're actually CHEAPER through GM.

^^X2 on that.
I also had to replace those and was surprised that you could get out of the dealership parts dept for so little $.