When I try to create a new element half of the window is cut of.
I've never encounterd that problem, but mae sure your resolution is high enough to see the whole window with extra space.
It's not a resolution problem.. this is happening to multiple people including myself and nobody is posting a solution.
Its because mcreator is a small community and no one has found a proper solution yet. There is no-one testing these bugs from pylo, if there was it is very small.