No...
It has nothing to do with POP mail.
Actually, I don't set Plus! to notify new email for me
.
It was Hotmail.
Let me re-tell it
I signed in and I got a notification that I had 2 new e-mails in my Hotmail account. I saw "2 new e-mail messages" on the top of the contact list.
But, after I reset the Plus! preferences, the "2 new e-mail messages" disappeared.
I just think that it's supposed to stay "2 new e-mail messages" although I reset Plus!.