Details
Description
When a CiviMail is sent and the mailing group it it sent to is subsequently deleted the CiviMail no longer appears in the civicrm interface.
Steps to recreate.
1) send a civimail to a group
2) delete the group
3) attempt to view the civimail record again
The records in civicrm_mailing_group remain after the group is deleted although they are now orphans but deleting this record is not sufficient to make the mail report accessible