Door trim
 

Not sure if its counted as door trim but the piece of plastic to the side of each pf the front seats under the door once closed has come off. It looks like it simply just slides on. I can get it part way on but not fully and it gets caught on the door when it is closed.

Anyone know how to reattach it properly?

Slide them inward making sure all the clips are aligned correctly for the slots behind that panel that came off. The clips are small white tabs and should not be broken in any way or skipped. It can be a tough-tight fit so be ready for some finger wear!

Hope I helped.