Apparently there is a little bug with the keys for resizing grid. I’m making modules from a laptop and the CTRL+Arrow keys are not working. I plugged an external keyboard it’s not working better. Then I tried to used the arrow keys from the numpad and these keys work .
So the resize grid is working with arrow keys from the numpad and the dedicated arrow keys not.
I’m with Vassal 3.1.10 under windows xp.