The sliding door section of the 3 season door appears to be attached with a long draw slide. The problem I had with the door after my first trip is that most of the screws vibrated out and the door was just hanging there when I got home. Upon checking, almost all the screws would not tight because they were stripped. These doors vibrate alot and maybe this is normal. I don't know.

My solution was thin double sided tape between the door and slide.
Relocate stripped screws to new holes and HAND tighten screws.
I think the frame is pretty thin, and it doesn't take much to strip the screws.
The door seems pretty solid now.

If you haven't done it, I would recommend it.