I have been trying to get the program to have two separate displays on each of my monitors (e.g. chase and cockpit) as I regularly do on my FS2014. I followed the instructions in the manual, whereby it told me to double the width pixel setting under the custom setting, and rather than the display stretching across my two screens, it went from the right hand screen out to the right, such that I could not see the selection boxes I needed to change, to get back to where I was before. I can only think I will have to re-install the complete software again, and still cannot see how I can get a different display (no problem duplicating the display) on my second monitor.
I have tried renaming the xplane_folder/Output/preferences/X-Plane Screen Res.prf file, but it made no difference.
I am running Windows 10, with two separate graphics outputs running as an extended display.
Any ideas, as this is a killer?