diff --git a/src/web/public/tile-grid.js b/src/web/public/tile-grid.js
index 74c457ac..c8c04f85 100644
--- a/src/web/public/tile-grid.js
+++ b/src/web/public/tile-grid.js
@@ -1535,7 +1535,10 @@ Object.assign(CodemanApp.prototype, {
     this.closeSessionSidebarOnHandheld?.();
     this.renderSessionTabs?.();
     const activeTab = document.querySelector(`.session-tab.active[data-id="${sessionId}"]`);
-    if (activeTab) {
+    // Not while it still glows: on every skin but OG the glow is `animation:
+    // none`, so animationend never comes and each tile focus used to leave
+    // another listener behind on the tab (49 after 50 focus changes).
+    if (activeTab && !activeTab.classList.contains('tab-glow')) {
       activeTab.classList.add('tab-glow');
       activeTab.addEventListener('animationend', () => activeTab.classList.remove('tab-glow'), { once: true });
     }
diff --git a/test/tile-grid-select-branch.test.ts b/test/tile-grid-select-branch.test.ts
index 3599f965..b52b1a91 100644
--- a/test/tile-grid-select-branch.test.ts
+++ b/test/tile-grid-select-branch.test.ts
@@ -19,7 +19,9 @@
  */
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import {
+  FakeEl,
   FakeTile,
+  bySelector,
   idleCallbacks,
   localStore,
   makeGridApp,
@@ -63,6 +65,29 @@ describe('selectSession with the grid open', () => {
     expect(app._focusedPane().sessionId).toBe('s-b');
   });
 
+  it('focus changes leave at most one glow listener on a tab, and the glow runs again once it ended', async () => {
+    // On every skin but OG the glow is `animation: none`: animationend never
+    // fires, and every focus used to add one more once-listener to the tab.
+    const app = openGrid();
+    const tab = new FakeEl();
+    tab.className = 'session-tab active';
+    bySelector.set('.session-tab.active[data-id="s-b"]', tab);
+    for (let i = 0; i < 5; i++) {
+      await app.selectSession('s-b');
+      await app.selectSession('s-a');
+    }
+    expect(tab.classList.contains('tab-glow')).toBe(true);
+    expect(tab.listeners.animationend).toHaveLength(1);
+
+    // OG: the animation ends, the class goes, and the next focus glows again.
+    tab.dispatch('animationend');
+    tab.listeners.animationend = [];
+    expect(tab.classList.contains('tab-glow')).toBe(false);
+    await app.selectSession('s-b');
+    expect(tab.classList.contains('tab-glow')).toBe(true);
+    expect(tab.listeners.animationend).toHaveLength(1);
+  });
+
   it('a user-initiated focus acknowledges the idle alert; an `auto` one does not', async () => {
     const app = openGrid();
     await app.selectSession('s-b');