So when I import roms, the core always defaults to RetroArch, which works most of the time. With MAME arcade games it's hit or miss. I try loading RetroArch and load the proper core that works with the game. However it doesn't save the core that it uses for that particular game. Or, it does with RetroArch itself, but when launching the game from Launchbox, it doesn't use the core that I saved.