Ok So I think I am getting close, I think it has to do with the Sim that holds the glass rail male to the rail female ( part 73626-01F00).
If you look at this picture, the part right behind the shade stopped moved freely up and down, where as the other side does not move.
And here is a GIF of the play I'm talking about in action. This happens when I git the glass a slight push up.
Any help would be appreciated.