It's the c:\Hitech Creations\Aces High\Settings\filters.cfg file. You can open it with Notepad. See that the first number in the lines ending with SMALLRECT and LARGERECT is positive. 1 is fine, it will align it nicely in the left. The last number on the same lines should be the same as your monitor's height, probably 1080, at the maximum. That will set the bottom. The meaning of the numbers is: Pixels from left, pixels from up, pixels from right and pixels from bottom.
1,900,1000,1080,SMALLRECT
1,32,1000,1080,LARGERECT
should probably work on a standard HD monitor. The sizes can then be changed with the mouse if desired.