diff --git a/app/src/protyle/wysiwyg/transaction.ts b/app/src/protyle/wysiwyg/transaction.ts
index f045f89cd..909bc35c9 100644
--- a/app/src/protyle/wysiwyg/transaction.ts
+++ b/app/src/protyle/wysiwyg/transaction.ts
@@ -692,7 +692,7 @@ export const onTransaction = (protyle: IProtyle, operation: IOperation, isUndo:
                 if (getContenteditableElement(rangeBlockElement)) {
                     range.insertNode(document.createElement("wbr"));
                 } else {
-                    getContenteditableElement(updateElements[0]).insertAdjacentHTML("afterbegin", "<wbr>");
+                    getContenteditableElement(updateElements[0])?.insertAdjacentHTML("afterbegin", "<wbr>");
                 }
             }
         }