To let the program know what type of monitor you have, you adjust a number that tells the program the monitor ratio. I am currently runnning Widescreen in a letterbox on my notebook LCD and the second monitor connected to it. I did not have to adjust the monitor directly.
When I mentioned
The way you explain it is actually an experiment on MA2-MD version.
I thought you were comparing it to the Beta version of Marine Aquarium 2 with multimonitor support.