Stephane,

AppRegistry is the abstract *superclass* of both MailSender and 
WebBrowser.  That explains why it has no references yet needs to be 
present.

Cheers,

   -- Scott

>But I could not find reference to it in 37a (may be this is because 
>I was not in full) but still
>MailSender and WebBrowser were there. I'm puzzled.
>Stef