From da8ff4a7b3a149172aa016c4fbca53ca94738526 Mon Sep 17 00:00:00 2001
From: Kan <25264536+kanlac@users.noreply.github.com>
Date: Thu, 7 May 2026 02:24:52 +0800
Subject: [PATCH 1/2] fix(tmux): enforce sidebar width after pane close

When a pane is killed, tmux redistributes window space and can shrink
or grow the sidebar pane. The pane-exited handler already ran to clean
up orphaned sidebars, but did not re-enforce the stored sidebar width.

Call scheduleClientResizeSync() after the orphan cleanup so the sidebar
is snapped back to its configured width, same as on a terminal resize.
---
 packages/runtime/src/server/index.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/runtime/src/server/index.ts b/packages/runtime/src/server/index.ts
index 7718c8d..4e01287 100644
--- a/packages/runtime/src/server/index.ts
+++ b/packages/runtime/src/server/index.ts
@@ -2285,13 +2285,15 @@ export function startServer(mux: MuxProvider, extraProviders?: MuxProvider[], wa
         return new Response("ok", { status: 200 });
       }
 
-      // pane-exited hook: a pane closed — kill orphaned sidebar panes
+      // pane-exited hook: a pane closed — kill orphaned sidebar panes and
+      // re-enforce sidebar width (tmux redistributes space when panes close)
       if (req.method === "POST" && url.pathname === "/pane-exited") {
         if (isSidebarVisible()) {
           invalidateSidebarPaneCache();
           for (const { provider } of listSidebarPanesByProvider()) {
             provider.killOrphanedSidebarPanes();
           }
+          scheduleClientResizeSync();
         }
         return new Response("ok", { status: 200 });
       }

From c63932551b154a565f4a1594f2fb7d032df1d1c6 Mon Sep 17 00:00:00 2001
From: Kan <25264536+kanlac@users.noreply.github.com>
Date: Thu, 7 May 2026 02:35:48 +0800
Subject: [PATCH 2/2] fix(tmux): replace pane-exited with after-kill-pane hook
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

pane-exited is silently ignored by tmux 3.4+ — set-hook accepts it
without error but show-hooks never lists it and it never fires. As a
result, orphaned sidebar cleanup and post-kill width enforcement have
never worked on modern tmux.

Replace with after-kill-pane, which fires reliably after kill-pane.
Also add after-kill-pane to HOOK_NAMES in tmux-sdk so the type is
correct and cleanupHooks can unset it on shutdown.
---
 packages/mux/providers/tmux/src/provider.ts | 7 ++++---
 packages/mux/tmux-sdk/src/index.ts          | 1 +
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/packages/mux/providers/tmux/src/provider.ts b/packages/mux/providers/tmux/src/provider.ts
index 55b2d3d..870404e 100644
--- a/packages/mux/providers/tmux/src/provider.ts
+++ b/packages/mux/providers/tmux/src/provider.ts
@@ -106,9 +106,10 @@ export class TmuxProvider implements MuxProviderV1, WindowCapable, SidebarCapabl
     tmux.setGlobalHook("after-new-window", ensureCmd);
     // client-resized: terminal window changed size — enforce stored width back
     tmux.setGlobalHook("client-resized", clientResizedCmd);
-    // pane-exited: a pane closed — kill orphaned sidebar panes (only pane left in window)
+    // after-kill-pane: a pane was killed — clean up orphaned sidebars and
+    // re-enforce width (pane-exited is not recognised by tmux 3.4+)
     const paneExitedCmd = hookPost("/pane-exited");
-    tmux.setGlobalHook("pane-exited", paneExitedCmd);
+    tmux.setGlobalHook("after-kill-pane", paneExitedCmd);
   }
 
   cleanupHooks(): void {
@@ -118,7 +119,7 @@ export class TmuxProvider implements MuxProviderV1, WindowCapable, SidebarCapabl
     tmux.unsetGlobalHook("after-select-window");
     tmux.unsetGlobalHook("after-new-window");
     tmux.unsetGlobalHook("client-resized");
-    tmux.unsetGlobalHook("pane-exited");
+    tmux.unsetGlobalHook("after-kill-pane");
   }
 
   getAllPaneCounts(): Map<string, number> {
diff --git a/packages/mux/tmux-sdk/src/index.ts b/packages/mux/tmux-sdk/src/index.ts
index 238a50b..d80988e 100644
--- a/packages/mux/tmux-sdk/src/index.ts
+++ b/packages/mux/tmux-sdk/src/index.ts
@@ -102,6 +102,7 @@ export const HOOK_NAMES = [
   "window-layout-changed",
   "after-select-window",
   "after-new-window",
+  "after-kill-pane",
   "after-resize-pane",
   "pane-died",
   "pane-exited",