can you please check out NATO - No Border Screen
it doesn't look right to me
Well, that's because this demo should be run in monochrome mode
Then, it tries to remove bottom border in hires, but this is not supported in Hatari yet, because monochrome mode doesn't show empty borders (as low/mod res do), so even if bottom border is removed, it would not be visible in the current window and also because the lo/hi switch to remove bottom border is not handled in Hatari.
I will try to add support for this later.