bcampeau/wordpress-fieldmanager-terms — pull request #1 by yllus (2012-11-22 16:44:26+00:00)
Title: Get all terms for the selected taxonomy (even the terms with no posts associated with them)

It appears that not all terms are returned - this turned out to be the fault of a default setting in WordPress that (if you ask me) is rather questionable: In get_terms(), hide_empty defaults to being true. I'll set this to false instead as we don't care if the terms has yet been used or not.