Arkaic

I'm playing in The 1.7.10 Pack, and in the options menu, I see this in the bottom right corner: "Press O to view more options". When I press O, it opens controls and filters for anything with "o" in it as part of the search bar, but doesn't actually open more options. I can't find a keybind or anything to change this or to open the additional options. Anyone know how I can open this to see what's there?