Starting today or last night whenever I press "Next" when there are no new messages in any of my IMAP accounts all of mozilla (every open window) hangs for 15-30 seconds and then returns to normal. check-all-imap-folders-for-new-mail is enabled, I have two IMAP accounts and a couple of news accounts. This worked fine (didn't do anything when no new messages were available) up until now.

Just had a hang for 1minute 10 seconds. It's almost painful to accidentally hit "Next" too many times...

This happens just crossing accounts, even if there indeed are unread messages in another account. Unless there's another bug addressing the delay... lots of navigation bugs, trying to keep them straight.

The bug I was thinking of regarding the extraordinary delay on Next across folders is bug 104610. From the description of this, I'd say they're one and the same problem. The word "hang" is used loosely here, not really a hang in the true sense. I'm going to mark this a duplicate of 104610 since that's already received nsbeta1+ approval and has more info/commentary. *** This bug has been marked as a duplicate of 104610 ***

marking verified as a duplicate