Krautmaster:
The problem is that the heavy grained vinyl has a layer of foam rubber on the back and that is what is glued to the plastic door panel frame. With heat & humidity the foam swells and pops the glue off the frame. I repaired mine by removing the door panel then removing the top 1" of foam from the back side of the vinyl by scraping it off with a butter knife (so as to not cut the vinyl). I then dampened the surfaces of the vinyl and plastic panel frame then applied a bead of GORILLA GLUE on the vinyl (Gorilla glue needs a damp surface for the chemical reaction to occur). I held it down by placing a piece of wood on the vinyl and using a boat load of duct tape to hold it tightly in place and let it dry overnight.

This will NOT work if you don't remove the foam rubber from the back of the vinyl (I tried repairing it twice without doing this and the foam just swelled up again) BTW, new door panels are $600-$700 each, Gorilla Glue about $5.

Note: remove the weatherstrip from the top of the door panel (it has 4-5 spring clips) and install it on the steel door frame (it has a channel that pushes down of the steel rim) before you try to reinstall the door panel. You can pop the spring clips into the door panel as you install it. I tried installing the door panel with the weather strip still attached to it and I could not get the strip to fit on the door frame (it was a nasty fight that did not go well).