Often times if I need to go back to an email I just tap 'mark as unread' so it remains bold in my Gmail stream. If you are like me you may be wondering where that option has disappeared to! (it used to be under the 3 vertical dots) Now you will find this option if you hover over the email when closed. Some options will appear to the right by the email date. The third grey option is 'Mark as read' or 'Mark as unread'. (open envelope = mark as read; closed envelope = mark as unread)
You can also access this option when the email is open. On the top right of the open email appears 3 vertical dots, click these dots for a menu of options including forward, print, and mark as unread.
