diff --git a/themes/classic/messenger/threadPane.css b/themes/classic/messenger/threadPane.css
index dcf4b2b9c114..84f3c37350c3 100644
--- a/themes/classic/messenger/threadPane.css
+++ b/themes/classic/messenger/threadPane.css
@@ -214,7 +214,7 @@ outlinerchildren:-moz-outliner-image(subjectCol, news, new, offline) {
   list-style-image: url("chrome://messenger/skin/icons/message-news-new-offl.gif");
 }
 
-outlinerchildren:-moz-outliner-image(subjectCol, news, offl) {
+outlinerchildren:-moz-outliner-image(subjectCol, news, offline) {
   padding-right: 2px;
   list-style-image: url("chrome://messenger/skin/icons/message-news-offl.gif");
 }