diff --git a/packages/ui-default/components/problemconfig/tree/Testcase.tsx b/packages/ui-default/components/problemconfig/tree/Testcase.tsx
index 3c849a59c..4db64927d 100644
--- a/packages/ui-default/components/problemconfig/tree/Testcase.tsx
+++ b/packages/ui-default/components/problemconfig/tree/Testcase.tsx
@@ -73,7 +73,7 @@ export function TestcaseGroup(props: TestcaseGroupProps) {
     item: { cases, subtaskId },
   }), [JSON.stringify(cases), subtaskId]);
   return <div
-    ref={drag}
+    ref={drag as any}
     onClick={onClick}
     onMouseDown={props.onMouseDown}
     onContextMenu={showContextMenu(