Running a Unity app in full screen with Xinerama

I’ve got a Unity application that otherwise runs fine. To make sure I wasn’t introducing any complexity, I made a unity application that displays a sphere. No animation, no interaction. Just a sphere.

When I run this application in full screen on Linux, it operates as one would expect.

When I turn the Xinerama option on and make a desktop across two monitors on the same GPU, then things get wonky. Instead of the full-screen surface, I only see a black screen. When I press the hot key combination to switch apps, when the screen is showing all of the running apps, I can see my application running and rendering there. When I give focus back to the application, it goes back to a black screen.

In doing a search, I’ve found reports here and there (separated by years) of people encountering similar issues with no actual solution. I don’t know if this is a Unity problem or an NVIDIA Xinerama problem. Any insight on this would be appreciated.

RHER 8.3, 64-bit
NVIDIA P2200