Karloss, right in one. :) All Stars was my test rom…the only one I had installed. Never occurred to me that the issue might be rom-related. A google search with All Stars shows this is a common issue, just as you said. DOH!
Thanks for the help, even though I’m somewhat chagrined that I didn’t figure it out myself. ;)
Is there a way to map the input_exit_emulator_btn to more than one controller?