Select / Chosen type_ahead incompatible with Term datasource

In our Post's term fields, we want to persist the assigned order so the first term assigned to a Post can be considered the "primary" term. Fieldmanager's Select Field with `type_ahead` and the term data source only works part of the way for this.

Using Chosen, I can assign terms to a post in arbitrary order. The terms are saved to the database correctly. However, because the `` is built with `` taxonomy terms in alphabetical order, my specified order is ignored for display (and lost when I save the post).

But, I think the bug is that `use_ajax` doesn't work with Chosen. For my term data source, I don't want to load all of the terms at once because it's a performance issue.