Problem with door panels

[nex]

I opened my drivers side door today, and I noticed what has the potential to be a big expensive problem. The corner of the door panel on the very bottom left corner of the drivers side door is loose, and whenever I open the door, it catches on the fender panel and like, bows out. What could I do to secure the panel back on firmyl and permenantly? should I get like industrial strength glue or something similar? Thanks!

 

[Defiant]

3M Trim and Badge tape. Wal*Mart. It'll last another decade.