diff --git a/lib/rails_admin/config/fields/types/polymorphic_association.rb b/lib/rails_admin/config/fields/types/polymorphic_association.rb
index 6977cca585..828b22c2a1 100644
--- a/lib/rails_admin/config/fields/types/polymorphic_association.rb
+++ b/lib/rails_admin/config/fields/types/polymorphic_association.rb
@@ -37,6 +37,10 @@ class PolymorphicAssociation < RailsAdmin::Config::Fields::Types::BelongsToAssoc
             nil
           end
 
+          register_instance_option :allowed_methods do
+            [children_fields]
+          end
+
           def associated_collection(type)
             return [] if type.blank?
             config = RailsAdmin.config(type)