Don't mark as read just by being shown in the preview window without a programmable (with default) timeout.
Leaving them as not read when moving to junk or deleted helps prevent feedback spam for messages that have read receipts attached to them.
If it's junk, I don't want the sender to know it got read or acknowledged in any form if all I'm going to do is move it to junk or delete it...
MailEnable survivor / convert --