From 01db0bfe862adf787f0c43625bea27e638f327d6 Mon Sep 17 00:00:00 2001
From: Abe Jellinek <jellinek@berkeley.edu>
Date: Wed, 19 Mar 2025 12:55:02 -0400
Subject: [PATCH] Fix occasional error when reader is closed immediately

---
 chrome/content/zotero/xpcom/reader.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/chrome/content/zotero/xpcom/reader.js b/chrome/content/zotero/xpcom/reader.js
index a82f2593c6..d690102881 100644
--- a/chrome/content/zotero/xpcom/reader.js
+++ b/chrome/content/zotero/xpcom/reader.js
@@ -621,7 +621,7 @@ class ReaderInstance {
 			this._prefObserverIDs.forEach(id => Zotero.Prefs.unregisterObserver(id));
 		}
 		this._flushState();
-		if (this._blockingObserver) {
+		if (this._blockingObserver && this._iframe) {
 			this._blockingObserver.unregister(this._iframe);
 		}
 	}