Contents When a message is unread, a red flag is displayed beside it. You will also see a red flag beside the icon for your Mailbox or a conference that contains unread messages. After you open an unread message, the red flag beside the message disappears. If you want this message to attract your attention again, you can put the flag back. To do this, select the message, then click Mark as Read. To remove this flag again, do the same thing. Shortcut Click the flag column beside the message to turn the flag off or on.