It's not terribly surprising - the USB-connected display introduces an additional driver. That USB driver is probably the big stumbling block here.
You've got that 22-inch main display, and the 7-inch display that's on an arm that rotates around the main display, and that 7-inch display can be turned either landscape or portrait at any time. I can't imagine what MA3 would look like on this configuration.
If windowed mode works, that sounds like your best alternative.