Nifty is not viewing changed screen

Hello all,
you can find the code here:
Now to the problem:
I have two methods in the GameState (Main/GameStates/ class which call a method in the menustate.
The thing is: in mainMenu(), it works, but in initClient(), it doesn’t. Even if I let it print out the screen name, it says “Main_Menu”, but in the window, nothing changes.

Robbi Blechdose

Error ? Nifty log ? Can you elaborate a bit more the issue ?