I won't, don't panic Steve, put the gun down.
LOL! But I'm on a mission. It ruined your tank game mate - but with the vsync on lovely and smooth - because you can't see the screen redrawing.
Seriously, this should be the default - which can be changed. But it does seem the sensible thing to do - else why use 2 screen banks at all when using one and the screen re-draw is evident?