You can view all the mails that are related or are bound by a parent mail. When you forward/reply to a mail, that mail is considered as a related mail of the original mail.
1. Select the mail whose related mails you wish to view.
2. This will display the related mail chain at the bottom of the mail.
3. Please note that a mail can have multiple related mails. The current mail you are viewing is highlighted.
4. You can click on the Subject of any of the related mails to view the message of that mail, and navigate to it to view the full details along with the attachments
5. You can choose to arrange/sort the mail thread based on the filters available on the right side options.