From e17d917afe102f02111aceff91237e47d1e0c6e0 Mon Sep 17 00:00:00 2001
From: Jinwoo Hong <73622457+Jinwoo-H@users.noreply.github.com>
Date: Thu, 16 Apr 2026 01:59:42 -0400
Subject: [PATCH] fix: prevent title bar flickering with multiple split-pane
 agents (#701)

---
 .../terminal-pane/pty-connection.ts           |  9 +++++++-
 .../use-terminal-pane-lifecycle.ts            | 23 ++++++++++++++++++-
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/renderer/src/components/terminal-pane/pty-connection.ts b/src/renderer/src/components/terminal-pane/pty-connection.ts
index 340f69aaa30..5b933e37362 100644
--- a/src/renderer/src/components/terminal-pane/pty-connection.ts
+++ b/src/renderer/src/components/terminal-pane/pty-connection.ts
@@ -98,7 +98,14 @@ export function connectPanePty(
   const onTitleChange = (title: string, rawTitle: string): void => {
     manager.setPaneGpuRendering(pane.id, !isGeminiTerminalTitle(rawTitle))
     deps.setRuntimePaneTitle(deps.tabId, pane.id, title)
-    deps.updateTabTitle(deps.tabId, title)
+    // Why: only the focused pane should drive the tab title — otherwise two
+    // agents in split panes cause rapid title flickering as each emits OSC
+    // sequences. Mirrors Ghostty's approach: only the active split's title
+    // propagates to the tab. When focus changes, onActivePaneChange syncs
+    // the newly active pane's stored title to the tab.
+    if (manager.getActivePane()?.id === pane.id) {
+      deps.updateTabTitle(deps.tabId, title)
+    }
 
     if (!hasConsideredInitialCacheTimerSeed) {
       hasConsideredInitialCacheTimerSeed = true
diff --git a/src/renderer/src/components/terminal-pane/use-terminal-pane-lifecycle.ts b/src/renderer/src/components/terminal-pane/use-terminal-pane-lifecycle.ts
index f2660b0605e..9304be555b8 100644
--- a/src/renderer/src/components/terminal-pane/use-terminal-pane-lifecycle.ts
+++ b/src/renderer/src/components/terminal-pane/use-terminal-pane-lifecycle.ts
@@ -304,13 +304,34 @@ export function useTerminalPaneLifecycle({
         // Dismiss the rename dialog if it was open for the closed pane,
         // otherwise it would submit against a non-existent pane.
         setRenamingPaneId((prev) => (prev === paneId ? null : prev))
+        // Why: PaneManager.closePane() reassigns activePaneId directly without
+        // calling setActivePane(), so onActivePaneChange does not fire. Sync the
+        // tab title to the survivor's stored title here so the tab label doesn't
+        // stay stuck on the closed pane's last title.
+        const newActivePane = managerRef.current?.getActivePane()
+        if (newActivePane) {
+          const paneTitles = useAppStore.getState().runtimePaneTitlesByTabId[tabId] ?? {}
+          const activeTitle = paneTitles[newActivePane.id]
+          if (activeTitle) {
+            updateTabTitle(tabId, activeTitle)
+          }
+        }
         scheduleRuntimeGraphSync()
       },
-      onActivePaneChange: () => {
+      onActivePaneChange: (pane) => {
         scheduleRuntimeGraphSync()
         if (shouldPersistLayout) {
           persistLayoutSnapshot()
         }
+        // Why: when the user switches focus between split panes, update the
+        // tab title to the newly active pane's last-known title so the tab
+        // label reflects the focused agent — not a stale title from the
+        // previously focused pane.
+        const paneTitles = useAppStore.getState().runtimePaneTitlesByTabId[tabId] ?? {}
+        const paneTitle = paneTitles[pane.id]
+        if (paneTitle) {
+          updateTabTitle(tabId, paneTitle)
+        }
       },
       onLayoutChanged: () => {
         scheduleRuntimeGraphSync()