make this class="dialog" so it looks like a normal dialog!

mailnews/news/resources/content/downloadheaders.xul

@@ -28,6 +28,7 @@ Rights Reserved.
 <window xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         orient="vertical"
+        class="dialog"
 		onload="OnLoad()">
 
 <script language="JavaScript" src="chrome://global/content/strres.js" />