I found the solution.

My games were opening on the left monitor (the "primary" now) but I knew there was a way to specify which monitor to open them on. But I forgot how. So, I Googled and came across this:

"You can also change your display settings to change what monitor a game opens on."

Make this my main display.jpg

Checked that box in my DISPLAY settings and, voila, center monitor has all that business in the right bottom corner (sorry, I don't know what it's called) and is now considered primary.

Thanks again, Fink. And thanks, Steve.