It happens to me too if i use fullscreen B option. Now i only use A.

Start the game and when you get to the menu:

If you have a saved game then the menu starts off selected at "continue" so do this:
When you are at the menu, press down once and press A (or whatever button it corresponds for you, im using controller on keyboard i believe its K), then up once and A, then down 4 times. Now you have selected the screen size option (or what its called, dont remember) and you can change setting going left/right.

If you do not have a saved game already then I think you have to press down 2 times instead of one at the menu, because its selected at Start a game, i think.

Edit: up/down on keyboard corresponds to W/S, left/right is A/D.

thanks for the tip!

Flipping thank you dude. Just started this up for the first time in ages and had this problem. I think the fact I've switch to a 4k screen since last time I played messed it up.