When I was selling parts from my other car, several people were looking for door panels because the flap that holds it in place was loose.
With my panel off for an extended period of time (dreaded C70 window problem), I decided to take a look at mine.
As you can see, the flap was loose. So I grabbed by good friend JB (Weld) and mixed up some epoxy. I put it under the flap and clamped it down (the more the merrier). I made sure to put wax paper between the clamps and the epoxy. In hindsight, I probably should have put something on the outside to cushion the clamps against the panel. There were indentations, but they came out over time.
Hope this helps anyone.