From 6425161befe34d1d3c409437734d086c44f24bbc Mon Sep 17 00:00:00 2001
From: jwcrystal <121911854+jwcrystal@users.noreply.github.com>
Date: Sun, 12 Apr 2026 04:42:02 +0800
Subject: [PATCH] fix(sidebar): auto-expand parent node when navigating to
 subagent session (#893)

When a user navigates to a subagent (child) session, the parent session
node in the left sidebar was not automatically expanded, making the
child session invisible in the tree. This change adds a useEffect that
detects when the current session has a parentID and automatically adds
that parentID to expandedParents, ensuring the subagent session is
visible in the sidebar hierarchy.
---
 .../src/components/session/SessionSidebar.tsx   | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/packages/ui/src/components/session/SessionSidebar.tsx b/packages/ui/src/components/session/SessionSidebar.tsx
index 7c9396f8..878eaf67 100644
--- a/packages/ui/src/components/session/SessionSidebar.tsx
+++ b/packages/ui/src/components/session/SessionSidebar.tsx
@@ -732,6 +732,23 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
       });
   }, [addProject, tauriIpcAvailable]);
 
+  // Auto-expand parent session when navigating to a subagent (child) session
+  React.useEffect(() => {
+    if (!currentSessionId) return;
+    const current = sessions.find((s) => s.id === currentSessionId);
+    const parentID = (current as Session & { parentID?: string | null })?.parentID;
+    if (!parentID) return;
+    setExpandedParents((prev) => {
+      if (prev.has(parentID)) return prev;
+      const next = new Set(prev);
+      next.add(parentID);
+      try {
+        safeStorage.setItem(SESSION_EXPANDED_STORAGE_KEY, JSON.stringify(Array.from(next)));
+      } catch { /* ignored */ }
+      return next;
+    });
+  }, [currentSessionId, sessions, safeStorage]);
+
   const toggleParent = React.useCallback((sessionId: string) => {
     setExpandedParents((prev) => {
       const next = new Set(prev);