Only extract parameters of non n

front/app/src/common/crud/types/foreignkey.type.ts

@@ -224,9 +224,11 @@ export class ForeignkeyTypeComponent extends FieldType<FieldTypeConfig> implemen
 
                 result = result.concat();
             } else if (typeof(obj[k]) == "object") {
+                if (obj[k]) {
                     result = result.concat(this.extractParameters(obj[k]));
                 }
             }
+        }
 
         return result
     }