Balsa's In-Reply-To header non-compliant?

[Peter Bloomfield <PeterBloomfield bellsouth net>]

Help me out here: RFC 2822 says that the In-Reply-To header is:

in-reply-to = "In-Reply-To:" 1*msg-id CRLF

where

msg-id = [CFWS] "<" id-left "@" id-right ">" [CFWS]

and CFWS is, of course, a _comment or _folding _white _space  
(comments are parenthesized).

So how does Balsa's

In-Reply-To: <20030921022718.GA12801@Mercury.localdomain>; from  
PeterBloomfield@bellsouth.net on Sun, Sep 21, 2003 at 04:27:18  
+0200

comply?  I don't see where "; lots of stuff" is [CFWS]!  What am  
I missing?

Peter