in your maximizer definition, each region should use the same 'game resolution'... this is the dimension just below pip hotkey.
click on each region and check.

also, those dimensions should be some multiple of your main region. on your main region, they should match the dimensions of the region... and on the smaller regions, the w,h should be some ratio of that dimension (eww... don't like how that worded...)

that make any sense at all??