A solution to eliminate the hide and seek game every time the MMU2S door is flipped.

No disassembly or extra components required, reuse existing tension screws and springs,

I printed the bases separately in a darker colour and I can guesstimate my tension from where the Thumbscrew ends. Use glue if you feel the need but mine are just pressed together (for now)

Assemble the Thumbscrew to the M3 x 30 screw

(TIP: placing screw into a drill chuck DO NOT TURN DRILL ON up to the base, aligning the hex inside the thumbscrew to the hex in the cap screw and then lightly tapping with a soft hammer)

Assemble the Thumbscrew Retaining assembly

(TIP: gently push the thumbscrew assembly into the retaining base by carefully spreading the opening apart, just enough to allow the cap screw part through)

The Thumbscrew should rotate and slide up and down freely inside the Retaining Base.

Slide the existing Tension Spring onto the thumbscrew assembly shank and into the Retaining Base.

(TIP: the spring is still lose at this point and can be lost, be careful)

Insert 1 x Thumbscrew Retaining Assembly into the matching cavity in the Idler Lid, left or right does not matter. (Edit) and insert the other in the other :) .

(TIP: IT DOES NOT REQUIRE MUCH FORCE. Push the Retaining Base all the way in without pushing on the Thumbscrew, this could break the sides of the retaining Base)

Assembly of the complete Thumbscrew Retaining Assembly is require prior to pressing into the MMU2S Idler lid.

TIP: when the base is fully inserted the thumbscrew can be pulled out of the retaining base relatively easily but it is not designed to push in without flexibility on the retaining base, it will break those tangs off

from: https://www.prusaprinters.org/cs/social/146481-terence