- parent = models.ForeignKey('self', null=True, blank=True, verbose_name=_('parent'), related_name="children")
- parent_number = models.IntegerField(_('parent number'), null=True, blank=True, db_index=True)
+ parent = models.ForeignKey('self', null=True, blank=True, verbose_name=_('parent'), related_name="children", editable=False)
+ parent_number = models.IntegerField(_('parent number'), null=True, blank=True, db_index=True, editable=False)