create an entity,
dock another entity to it
put a flip flop connected to a delay or any other type of signal (havent tested all logic blocks with this) and connect the delay/other logic gate to the flip flop and activate the flip flop,
you get the null pointer error, and when you relog, you find that everything you have done after you have gotten the null pointer, it never really happened,
and also, seems that you dont get disconnected, you just keep getting the error consistently