In OE6 I've got a mail rule for spam (marked by K9) that
just moves the mail to a folder and marks it as read.
Whenever I receive spam I still get the new mail icon
popping up in the system tray, even though the mail rule
has marked it as read. To get rid of the icon I have to
actually read an old mail. This is making the new mail
icon completely useless as I receive about three times as
much spam as real mail.
Similarly, if I receive a mail on one account and read it
before OE has finished downloading from the other
accounts, then I still get the new mail icon despite the
fact I've already read the new mail.