Actually, as far as I'm aware, this feature (new in JSF2) is just a convenience that permits the SelectItem collection to be constructed automatically.
Technically, it's not an iterator, either. It's an expression of a linear collection (or array), just as a dataTable is an expression of a 2-dimensional collection. LISPers and other such evil people will be glad to point out that actual iteration to express such constructs is purely optional. Don't you just love pedantry? :)
An IDE is no substitute for an Intelligent Developer.