I'm seeing the same thing, @support. Some games show up on the SCREEN2 (the main one) and others on SCREEN1 (the marquee. They are oriented 2->1 again where 2 is main and 1 is marquee. It's unusable in this state. And no art appears anywhere.
I think if screen orientation matters to your software, then you should detect when "screen geometry" changes in Windows (happy to help explain the Win32 ramifications if needed) and reset them or guide the user to reset them.
SUPPORT: Note that if I run (example) mame -v pacman > test.txt to get a log, I see:
Video: Monitor 983553 = "\\.\DISPLAY1" (primary)
Video: Monitor 1114657 = "\\.\DISPLAY2"
That's wrong, of course, even though I see you tried in mame.ini to set screen to DISPLAY2.
I CHANGED" C:\Users\Polycade\AppData\Roaming\polycade\emulators\mame\mame.ini" after encounterin this bug to DISPLAY1 (as it's listed as primary) and it worked. @Beartrap this will likely fix you, but make a backup!
#
# OSD PER-WINDOW VIDEO OPTIONS
#
screen \\.\DISPLAY1
screen0 \\.\DISPLAY1
screen1 \\.\DISPLAY1
screen2 \\.\DISPLAY1
screen3 \\.\DISPLAY1
But to be clear, Polycade, you have a bug here for marquee owners.
