Reply-To field depopulates when saving then continuing a draft mailing

Steps to reproduce on demo site:

1. Enable Custom Reply-To here: http://d46.demo.civicrm.org/civicrm/admin/mail?reset=1
2. Create a new mailing, filling out all required fields and such. Make sure you select an email address for both the From and Reply-to fields
3. Save the message as a Draft by clicking the Save Draft button
4. From the Draft and Unscheduled Mailings page click the "Continue" link to the right of the mailing you just saved: http://d46.demo.civicrm.org/civicrm/mailing/browse/unscheduled?reset=1&scheduled=false
5. The Reply-to field will be blank