Support nested fieldsets in administration

[Archatas]

Administration options should allow to have nested fieldsets for grouping fields in a more organized way.

For example,

# -*- coding: utf-8 -*-
from django.utils.translation import ugettext_lazy as _
from django.contrib import admin
from halmastar.apps.sandbox.models import Contact

class ContactAdmin(admin.ModelAdmin):
    fieldsets = (
    (_("Main Info"), {'fields': ("user", "website")}),
    (_("Phones"), {'fields': (
        (_("Primary"), {'fields': (("primary_phone_country", "primary_phone_area", "primary_phone_number"),)}),
        (_("Secondary"), {'fields': (("secondary_phone_country", "secondary_phone_area", "secondary_phone_number"),)}),
        )}),
    )

admin.site.register(Contact, ContactAdmin)

The key 'fields' point to a list of field names, field-name tuples, or fieldset definitions.

[Archatas]

An example of nested fieldsets

[Archatas]

The patch for nested fieldsets

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Aymeric Augustin]

Thanks for the proposal, but there doesn't appear to be a lot of demand for this feature, and I'm not convinced it's a win for the UX.

I suggest using custom CSS classes — the admin provides appropriate hooks to set CSS classes on fieldsets and to inject custom CSS.