diff --git a/mozilla/mailnews/base/prefs/resources/content/pref-tags.js b/mozilla/mailnews/base/prefs/resources/content/pref-tags.js
index f4f4861e4b8..368aaf15ad3 100644
--- a/mozilla/mailnews/base/prefs/resources/content/pref-tags.js
+++ b/mozilla/mailnews/base/prefs/resources/content/pref-tags.js
@@ -58,7 +58,7 @@ var gDeleteButton = null;
 var gRaiseButton  = null;
 var gLowerButton  = null;
 
-var gDeletedTags  = null; // tags marked for deletion in non-instant apply mode
+var gDeletedTags  = {}; // tags marked for deletion in non-instant apply mode
 
 
 function Startup()