From 9e6998bc1a3abe06a56b52d2878993f2f416188f Mon Sep 17 00:00:00 2001
From: "mr. m" <mr.m@tuta.com>
Date: Fri, 2 Jan 2026 00:18:51 +0100
Subject: [PATCH] feat: Take into account tab entry index may not exist,
 b=no-bug, c=no-component

---
 src/zen/sessionstore/ZenWindowSync.sys.mjs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/zen/sessionstore/ZenWindowSync.sys.mjs b/src/zen/sessionstore/ZenWindowSync.sys.mjs
index 7e041196b..61808b8d4 100644
--- a/src/zen/sessionstore/ZenWindowSync.sys.mjs
+++ b/src/zen/sessionstore/ZenWindowSync.sys.mjs
@@ -822,8 +822,11 @@ class nsZenWindowSync {
     return lazy.TabStateFlusher.flush(aTab.linkedBrowser).finally(() => {
       this.log(`Setting pinned initial state for tab ${aTab.id}`);
       const state = this.#getTabState(aTab);
+      let activeIndex = 'index' in state ? state.index : state.entries.length - 1;
+      activeIndex = Math.min(activeIndex, state.entries.length - 1);
+      activeIndex = Math.max(activeIndex, 0);
       const initialState = {
-        entry: state.entries[state.index - 1],
+        entry: state.entries[activeIndex],
         image: state.image,
       };
       this.#runOnAllWindows(null, (win) => {