old_contents: from django.contrib.admin import RelatedFieldListFilter
  from django.utils.encoding import smart_text
  from django.utils.html import format_html
  from django.core.urlresolvers import reverse
  
  try:
      from django.contrib.admin.utils import get_model_from_relation
  except ImportError: # Django 1.6
      from django.contrib.admin.util import get_model_from_relation
  
  try:
      from django.forms.utils import flatatt
  except ImportError: # Django 1.6
      from django.forms.util import flatatt
  
  
  class RelatedFieldAjaxListFilter(RelatedFieldListFilter):
      ajax_attrs = None
  
      def has_output(self):
          return True
  
      def field_choices(self, field, request, model_admin):
          model = field.remote_field.model if hasattr(field, 'remote_field') else field.related_field.model
          app_label = model._meta.app_label
          model_name = model._meta.object_name
  
          self.ajax_attrs = format_html('{}', flatatt({
              'data-app-label': app_label,
              'data-model': model_name,
              'data-ajax--url': reverse('jet:model_lookup'),
              'data-queryset--lookup': self.lookup_kwarg
          }))
  
          if self.lookup_val is None:
              return []
  
          other_model = get_model_from_relation(field)
          if hasattr(field, 'rel'):
              rel_name = field.rel.get_related_field().name
          else:
              rel_name = other_model._meta.pk.name
  
          queryset = field.related_model._default_manager.filter(**{rel_name: self.lookup_val}).all()
          return [(x._get_pk_val(), smart_text(x)) for x in queryset]
  
new_contents: from django.contrib.admin import RelatedFieldListFilter
  from django.utils.encoding import smart_text
  from django.utils.html import format_html
  from django.core.urlresolvers import reverse
  
  try:
      from django.contrib.admin.utils import get_model_from_relation
  except ImportError: # Django 1.6
      from django.contrib.admin.util import get_model_from_relation
  
  try:
      from django.forms.utils import flatatt
  except ImportError: # Django 1.6
      from django.forms.util import flatatt
  
  
  class RelatedFieldAjaxListFilter(RelatedFieldListFilter):
      ajax_attrs = None
  
      def has_output(self):
          return True
  
      def field_choices(self, field, request, model_admin):
          model = field.remote_field.model if hasattr(field, 'remote_field') else field.related_field.model
          app_label = model._meta.app_label
          model_name = model._meta.object_name
  
          self.ajax_attrs = format_html('{}', flatatt({
              'data-app-label': app_label,
              'data-model': model_name,
              'data-ajax--url': reverse('jet:model_lookup'),
              'data-queryset--lookup': self.lookup_kwarg
          }))
  
          if self.lookup_val is None:
              return []
  
          other_model = get_model_from_relation(field)
          if hasattr(field, 'rel'):
              rel_name = field.rel.get_related_field().name
          else:
              rel_name = other_model._meta.pk.name
  
          queryset = model._default_manager.filter(**{rel_name: self.lookup_val}).all()
          return [(x._get_pk_val(), smart_text(x)) for x in queryset]
  
subject: Fix queryset