From d8e3eb94b4d4a8ad17cab292d81f49ab4e029f41 Mon Sep 17 00:00:00 2001
From: JJ Lee <jeonghun.jj.lee@gmail.com>
Date: Tue, 11 Aug 2026 00:38:16 +0200
Subject: [PATCH] fix(session-header): await session sync before navigation
 from titlebar flyout
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When switching sessions within the same route (params.id change from the
titlebar sessions flyout), the Page component persists and the timeline
re-keys immediately. If session data isn't fully cached yet, rows trickle
in and the measurement burst overlaps with user interaction — the
virtualizer's scroll anchoring snaps the viewport back to the bottom.

The dashboard doesn't have this issue because it navigates to a different
route pattern, causing a full component remount where messagesReady()
naturally gates the timeline from false→true with complete data.

Fix: await serverSync().session.sync(id) before calling navigate(). This
ensures messages + parts are fully in cache when the timeline mounts,
eliminating the trickle-in measurement burst. For already-cached sessions
(tab strip pre-sync, previous visits) this resolves instantly — no
perceptible delay.

Also mirrors the dashboard's ctx.projects.open/touch setup to warm the
workspace context.

Closes #176
---
 .../src/components/session/session-header.tsx | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/packages/app/src/components/session/session-header.tsx b/packages/app/src/components/session/session-header.tsx
index 260fc4a71..c05e7d479 100644
--- a/packages/app/src/components/session/session-header.tsx
+++ b/packages/app/src/components/session/session-header.tsx
@@ -785,9 +785,29 @@ function SessionChatsDropdown() {
     }
   }
 
-  function openSession(session: Session) {
+  async function openSession(session: Session) {
     // Close flyout first so its Portal unmounts cleanly.
     setOpen(false)
+
+    // Mirror the dashboard's project setup: ensure the directory is registered and
+    // touched so the workspace context is warm when the session page mounts.
+    const conn = server.current
+    if (conn) {
+      const ctx = globalCtx.ensureServerCtx(conn)
+      ctx.projects.open(session.directory)
+      ctx.projects.touch(session.directory)
+    }
+
+    // Await session sync BEFORE navigating (issue #176). When switching sessions
+    // within the same route (params.id change), the Page component persists and
+    // the timeline re-keys immediately. If data isn't fully cached yet, rows
+    // trickle in and the measurement burst overlaps with user interaction, causing
+    // the virtualizer's scroll anchoring to snap the viewport back. Awaiting here
+    // ensures messagesReady() is true with complete data the moment the timeline
+    // mounts — matching the dashboard path where the fresh route mount naturally
+    // gates on messagesReady(). For already-cached sessions this resolves instantly.
+    await serverSync().session.sync(session.id).catch(() => {})
+
     // Use tabs.select for sessions that already have an open tab (no transition).
     // For sessions without a tab, navigate directly — DO NOT use tabs.openPath
     // which calls addSessionTab(startTransition), keeping both old and new UI