What do you mean by that?
As in: in and out when you wobble it back and forth, or is it side to side (so front to back), almost like it's tiltight forward and backward?
I'm thinking that could also be the felt/whisker covered glass locators that position the glass. They may have just wore down, or most likely just need adjusting.
Take a look at the attched photo. This is a coupe door, but you'll spot the two locators pushing against the glass. They are bolted down and as you can tell can be adjusted accordingly.