unique option

[Bless]

When you use meta.ForeignKey ([] ,unique=True) or a field with 'choices=... ,unique=True' option, it would be well that the select box in form could show us the valid options only.

[Adrian Holovaty]

There are a couple of problems with this idea: Mainly that, if the form displays only the available options, and somebody *else* makes a change so that the options change, the admin form will be out of sync with reality.