I added a second monitor this week, so I could full-screen sim on one, and have charts on the other. In X-Plane Graphics Settings I have Monitor 1 (the monitor in front of me) set to "Full Screen Simulator". The Main Monitor (the monitor to my right) is set to "Unused". In Windows, the monitor in front of me is Monitor 2, the monitor to my right is Monitor 1 and is selected as "Make this my main display". I also have selected in Windows "Extend these Displays". In this configuration, when I try to pop out the Garmin panels, the Garmin pop out is somewhere off screen. Nothing I've tried will get it to pop up on screen. This is problematic for me.
If I switch the monitors around in Windows (make the monitor in front of me the main display) and reconfigure X-Plane 11 to use Main Monitor for "Full Screen SImulator" and Monitor 1 to "Unused", the popups display correctly.
Is this an artifact of X-Plane itself? The AFM Mooney Ovation III? Weird interaction with Windows?