[fredjacksonsan]

You're right, hard to tell without a picture. If you can post one up, that would be good.

But that said, is the window frame one piece with 3 posts going into the door? Do the posts enter into plastic sleeves or slots? If so, you might have the newer style door. If this is true, then you can simply grasp the top portion near the front and rear, and pull straight up. It will come out of the door. To replace, put the front post in first, then line up the other two and push into place.

Hope that helps; if you don't have the newer version then post up a picture.