I uncovered a bug in the new Yahoo Mail. Here are the details.

1. Send an e-mail to someone.
2. Go into your Sent folder and open up that e-mail.
3. Hit Reply All (your e-mail won't appear in the To: field).
4. Send that follow-up e-mail.
5. The title bar in your web browser will flash saying that you have 1 new message.
6. However that isn't the case. There are no new e-mails in your inbox.
7. Perhaps the message is telling you that you have a new message in your Sent folder ... but that doesn't make sense. When you see a notification about a new message you would naturally assume you got new e-mail in your Inbox, but that isn't the case here.

I don't remember this being a problem in the old Yahoo Mail. I only noticed this in the new Yahoo Mail.