Driver's seat back loose
 

My '06 R53 driver's plastic seat backing has been popping off at the top with increasing regularity. It's the piece marked as #2 'rear panel' on:

http://www.realoem.com/bmw/showparts...57&hg=52&fg=10

Anyone with similar issues/possible fixes? It tends to happen under moderate acceleration and as a temporary fix, I've just been pushing it back into place. The driver's side is much looser than the passenger side.

Searched for a while here and on the mini2 forums. Only a few (very old) mentions at the mini2 forums, no solutions.