Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3282741.

One of the first things that happened when I assembled my MMU2 was the screw fell out when opening the assembly to gain access to the filaments. I almost lost one of the springs.

I modified Prusa's control board cover and extended it to add a keeper for the screws. You can still see to adjust the screws and you can open the head fully without worrying about them falling out. You can still remove the screw fully by removing the control board cover.