These clips are well known for falling off when you remove the switches from the ashtray surround. After I'd removed mine, I took the clips off the switch and then put a dot of superglue on the side of each of the switches and then slotted the metal clips back in place. Let them dry for a couple of minutes before reinstalling the switches in the surround.
Also, when you're first removing the surround before you unclip the switches, lift up the front of the surround and slide a cloth underneath where the switches are so that when the clips do fall off, you'll catch them on the cloth.
Hope that helps!
