To show you what i mean about the rattling, i took before and after videos of the rattling noise in the door panels after inserting little shards of t-shirt material into the free space between the white connector and its housing. The difference is pretty dramatic...
BEFORE - door panel rattling
AFTER - door panel sound after sound deadening (cloth material insertion)
And no, i did not turn off the audio in the 2nd video lol. Again, the RAW rattling sound will naturally go away on its own after you re-insert the door panel to the door (just due to pressure of the door panel being attached to the door), but the bare plastic rubbing against bare plastic situation will not, unless there is some buffering there.
The point of the AFTER video is to show you not that the rattle went away, but that a layer of cloth was inserted between these two parts to buffer them from each other, to prevent the squeaking from being generated when the car is in motion.
What can't rub against each other.... can no longer produce noise
