diff --git a/chrome/content/zotero/integration/quickFormat.js b/chrome/content/zotero/integration/quickFormat.js
index cbcf0a8d1a..82962698e7 100644
--- a/chrome/content/zotero/integration/quickFormat.js
+++ b/chrome/content/zotero/integration/quickFormat.js
@@ -221,7 +221,7 @@ var Zotero_QuickFormat = new function () {
 	 */
 	var _quickFormat = Zotero.Promise.coroutine(function* () {
 		var str = _getEditorContent();
-		if (str.match(/\s$/)) {
+		if (str && str.match(/\s$/)) {
 			locatorLocked = true;
 		}
 		var haveConditions = false;