Steve,
I don't know what the filtering bug was, but I think I may have run into another filtering problem:
I select a custom game list, go into the filtering options, select the category filters, and select the "show all categories" option. MAMEWAH filters the games, and I suddenly end up with about 1800 games instead of 3500-ish. Also, all the games have just their name listed, instead of the "Asteroids (rev2)" style listing.
I'm more than willing to chalk this up to "user error", but I can't figure out why it's cutting my game list in half (and changing the way the games are displayed.)
Any ideas?
Kevin