Only extract parameters of non n

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

@@ -224,7 +224,9 @@ export class ForeignkeyTypeComponent extends FieldType<FieldTypeConfig> implemen
 
                 result = result.concat();
             } else if (typeof(obj[k]) == "object") {
-                result = result.concat(this.extractParameters(obj[k]));
+                if (obj[k]) {
+                    result = result.concat(this.extractParameters(obj[k]));
+                }
             }
         }