diff --git a/mail/components/addrbook/content/addressbook.xul b/mail/components/addrbook/content/addressbook.xul
index ec97010df09..4cb0e393197 100644
--- a/mail/components/addrbook/content/addressbook.xul
+++ b/mail/components/addrbook/content/addressbook.xul
@@ -192,6 +192,7 @@
   <menuitem id="dirTreeContext-delete"
             label="&deleteButton.label;"
             accesskey="&deleteButton.accesskey;"
+            observes="button_delete"
             oncommand="goDoCommand('button_delete');"/>
 </popup>