I have a site on which I have unsealed and added columns to a content type, 'Folder'. Now, I want to add this content type to a document library, but I do not have the option to add it in Document Library Settings -> Add from existing site content types. I'm not seeing the "Folder Content Types" in the Groups drop-down menu. Also, if I move the content type to another group that does show up in this drop-down, it still doesn't appear. Is there something I have to do to make this content type a choice for my document library or a place to choose which content type groups are usable for a site?
Thanks very much