Limit root nav auto-expansion

Only auto-open a section root sidebar when it has a single top-level folder, avoiding the fully expanded Reference nav while preserving single-TOC sections.

Co-Authored-By: GPT-5.5 <noreply@openai.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

Author: 3 people

src/Elastic.Documentation.Site/Assets/pages-nav-v2.ts

@@ -616,13 +616,12 @@ function expandToCurrentPageForPath(nav: HTMLElement, pathnameRaw: string) {
  */
 function expandToCurrentPage(nav: HTMLElement) {
     if (isOnSectionRootPage(nav)) {
-        // On the section root page, expand all top-level folders so the
-        // section content is visible even though no specific page is current.
-        nav.querySelectorAll<HTMLInputElement>(
+        const topLevelFolders = nav.querySelectorAll<HTMLInputElement>(
             '#nav-tree > li > .peer > input[type="checkbox"]'
-        ).forEach((cb) => {
-            cb.checked = true
-        })
+        )
+        if (topLevelFolders.length === 1) {
+            topLevelFolders[0].checked = true
+        }
         return
     }
     expandToCurrentPageForPath(nav, window.location.pathname)