The buttons from "More World Options" are not in their own menu:

Dude you have Modern World Creation installed, it can't work with that. And even if not installed, the world creation screen isn't fully customizable yet, because of the overlapping buttons that kill FancyMenu's button customization system. Overlapping buttons will be customizable in the next update I'm currently working on.

It does seem to work with Modern World Creation for the most part, the issue is the overlapping buttons. Didn't know they weren't supported yet.