In the message, I can't mouse over any of the recipients or senders like in the previous version 3.1. The email address don't show only display name.
I've had this happen before to me. None of the mouse over stuff works; email addresses, web links, dates, etc. Usually I just log off/log back in and everything is restored. My OS and client of choice are Linux (FC6) and Firefox 2.0; haven't noticed it on Windows and/or IE, although I don't use them that often.