Comment 8 for bug 90824

A more common case...

What Happened:
  I selected two or more NEW messages in a non-trash folder and press
  Delete. I then right click on Trash and select "Mark Folder Read".
  The folder blinks read for a second, then goes back to being unread.

What I expected:
  If I throw something away and then try to mark the trash folder
  read, then it should happen.

Notes:
  Given comment #6, I would suggest that when a message is
  copied from one folder to another that the header is either:
  immediately reread OR it is copied with the email. I don't know
  enough about IMAP or whatever to know if that's reasonable or not.

  I supposed that there could be problems with, for example, copying
  5000 emails.

  I also wonder what the user expects. If they see a folder with
  unread messages and they don't *visit* the folder and want to mark
  it read, then shouldn't it be marked read?

  Perhaps there is a better way to show the user that there are
  messages they could not have seen vs. message they haven't read.

  For example:
    Folder foo has 2 unread messages. I click on foo and see the
    subject lines of the messages. I then click on INBOX. A new
    message arrives in folder foo. It has 1 unseen message and 3
    unread messages.

    Perhaps color could denote this:
      If all messages are seen and read: black, normal font-weight
      If unseen messages exist: purple, bold
      If all messages are seen, but some are unread: blue, bold

    Sort of like default web links.

Ciao!