diff --git a/templates/modern/src/toc.ts b/templates/modern/src/toc.ts
index de7158bb1f4..9cfc349e28e 100644
--- a/templates/modern/src/toc.ts
+++ b/templates/modern/src/toc.ts
@@ -56,6 +56,9 @@ export async function renderToc(): Promise<TocNode[]> {
       node.href = url.href
       active = normalizeUrlPath(url) === normalizeUrlPath(window.location)
       if (active) {
+        if (node.items) {
+          node.expanded = true
+        }
         selectedNodes.push(node)
       }
     }