there are many ways to say poo...some correct, some not so, but we all seem to understand it.
You see many many repeated posts here of "why did my slide not stay open on empty" or "why did my slide lock back with rounds in the mag".
I think the upper stop lever release lock widget tab thingy is a PIA for many right handers with thumbs. It certainly is a perfect and comfortable thumb rest for the thumbs forward combat hold. Its the least reliable control on the Glock.
The best solution is to chop the thumb at the first joint behind the nail. Easy fix, only bleeds for a little bit.