This is a first for me.
Using Mail. There's an email with grayed-out subject line. Can't delete it. When clicking on it there's an 'Undelete' button that appears on top which I've never seen before, and that doesn't work. I did everything else under the sun to get rid of it, but it won't go away.
I quit and re-launched Mail
I right-clicked the subject line
I opened it
I dragged it
Junked it, bounced it, etc.
Still, it remains.
Email is from MacUpdate so it's legit as far as I'm concerned.
Any ideas?