When drawing (specifically with a drawing tablet) and you press ctrl z (undo) (with your pen on the virtual paper) then remove the pen from the paper, the entire layer will be stuck to your pen, and every time you touch something in the program, including both drawing and the close buttons you will get an error and will be forced to close the program with task manager. I have the steam version with its auto updates so it should be up to date.
to replicate bug simply touch a pen to a drawing tablet then press ctrl, z
when using a drawing tablet it will cause the crash every time
when using mouse it seems to work fine