add more_admin_filters

pyproject.toml

@@ -26,6 +26,7 @@ python = ">=3.7.2,<4.0"
 Django = ">=3"
 django-polymorphic = "^3"
 celery = ">=4.4"
+django-more-admin-filters = "^1.7"
 
 [tool.poetry.group.dev.dependencies]
 flake8 = "^5.0.4"

tests/app/settings.py

@@ -38,6 +38,7 @@
     'django.contrib.sessions',
     'django.contrib.messages',
     'django.contrib.staticfiles',
+    'more_admin_filters',
     'polymorphic',
     'triggers',
     'tests.app',

triggers/admin.py

@@ -3,6 +3,7 @@
 from django.contrib import admin
 from django.utils.html import format_html_join
 from django.utils.translation import gettext_lazy as _
+from more_admin_filters import MultiSelectRelatedOnlyFilter
 from polymorphic.admin import PolymorphicInlineSupportMixin, StackedPolymorphicInline
 from polymorphic.models import PolymorphicModel
 
@@ -52,7 +53,7 @@ class EventInline(StackedPolymorphicInline):
     child_inlines = generate_child_inlines(Event)
 
 
-class RelatedOnlyFieldListFilter(admin.RelatedOnlyFieldListFilter):
+class RelatedOnlyFieldMultiListFilter(MultiSelectRelatedOnlyFilter):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.title = self.__class__.__dict__['title']
@@ -64,7 +65,8 @@ def field_choices(self, field, request, model_admin) -> List[Tuple[str, str]]:
 
 
 def create_related_filter(title):
-    return type('_RelatedFilter', (RelatedOnlyFieldListFilter,), {'title': title})
+    return type('_RelatedFilter', (RelatedOnlyFieldMultiListFilter,), {'title': title})
+
 
 
 @admin.register(Trigger)