Driver side mirror cover question
 

Hi-
I'm leasing a 2019 Civic 2.0L 4D LX. The driver side mirror cover came off. No idea how; it was just lying in my driveway and there's no way I would've missed it had I been in the car at the time. It's not cracked and the mirror itself is fine. I just sort of snapped it back on and it looks right, but I don't want to be driving and have it come off if I didn't replace it correctly. It feels pretty solid, but is there anything more to it?
TIA-

-Susan