I changed out a bad circuit breaker for the first time today. When I went to remove the (Siemens) front plate, I noticed that the metal surrounding the circuit breakers is a different piece from the main plate (that the door attaches to) and has two screws that are different from the rest of the screws holding the door in.
I thought, "Hey, great, they've designed it so that I can just take out the center panel without having to remove the whole face and door!" Except, as shown above, the separate insert is behind the front plate. Removing those screws does nothing useful (it's still caught on the breakers protruding through the slots). I had to remove the entire plate and door to change the breaker.
What is the purpose of having the plate & door separate from the center panel? Why is one detachable from the other?