Sets is_popup context variable to hide admin header.

def delete_view(self, request, object_id, extra_context=None):
        """Sets is_popup context variable to hide admin header."""
        if not extra_context:
            extra_context = {}
        extra_context['is_popup'] = request.REQUEST.get('_popup', 0)
        return super(EnhancedAdminMixin, self).delete_view(request, object_id, extra_context)