diff --git a/src/components/LeftMenuBar.vue b/src/components/LeftMenuBar.vue
index abca934d..1d6dc7b8 100644
--- a/src/components/LeftMenuBar.vue
+++ b/src/components/LeftMenuBar.vue
@@ -86,7 +86,7 @@ export default {
     });
   },
   setup(props, context) {
-    const index = ref(null);
+    const index = ref(0);
     const route = useRoute();
     const menus = reactive(
       props.list.map((first) => {