Dual Monitor setup issue... worked before I switched input sources on one monitor

I have two monitors, one on top of the other, the bottom one being the primary/main, and the top one being the extended display, for a Mac. I switched inputs on the top monitor from display port to HDMI. I updated the firmware on the bottom monitor... but now, no matter what I do, all the snap areas have moved to the top monitor, which I don't need. Is there a "set primary monitor" option I don't see? Nothing I've tried will get the snaps back where they were on the lower/main monitor. Thanks in advance.