The tab button doesn’t bring up that menu in MAME for me, it has no response. I can get a similar read-only menu by hitting “select” and “x” as I have them mapped on my controller right now, but I can’t edit anything in there (or I haven’t figured out how). The read file I can open also looks a little different, it doesn’t have any specific letter buttons like “coin 1” or “1 player start.”