How to define file types which appear in "New" menu

I don't know when exactly that happened, but a lot of file types disappeared from the "New" menu. E.g. when I'm in Scala project, the file types I can create from "New" menu are: File (a generic one), Directory, HTML File, XSLT Stylesheet. There's no: Scala file, Scala Worksheet or even Package available on that list. How can I add these file types to that list? Is it configured per plugin or per project type? How can I reset that specific setting to defaults (I didn't change that, but it's obviously wrong). I'm using Idea 14.0.3 with Scala 1.3.2 plugin on Mac.