Sent emails should not appear when Unread filter is used.
The Unread email link in the left menu, clicking this displays unread emails, but it also displays Sent emails - I'm not sure why this occurs as all sent emails have been read, as I'm the sender!
This looks to be fixed now.
Rick Reno commented
You have an "unread" option, but when I click on it it brings me to all my SENT messages, which are, of course, unread. Bad design. Allow the sent folder to be excluded from Unread sections.