From 319db401c2e7decb3e8839d44a2a1b9bee4c3794 Mon Sep 17 00:00:00 2001
From: Vanessa <lly219@gmail.com>
Date: Sat, 20 Dec 2025 11:23:26 +0800
Subject: [PATCH] :art: https://github.com/siyuan-note/siyuan/issues/16640

---
 app/src/protyle/wysiwyg/transaction.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/src/protyle/wysiwyg/transaction.ts b/app/src/protyle/wysiwyg/transaction.ts
index ffec4eff0..1531e34dc 100644
--- a/app/src/protyle/wysiwyg/transaction.ts
+++ b/app/src/protyle/wysiwyg/transaction.ts
@@ -319,7 +319,7 @@ const updateEmbed = (protyle: IProtyle, operation: IOperation) => {
 };
 
 const deleteBlock = (updateElements: Element[], id: string, protyle: IProtyle, isUndo: boolean) => {
-    if (isUndo) {
+    if (isUndo && updateElements[0]) {
         focusSideBlock(updateElements[0]);
     }
     updateElements.forEach(item => {