We have a customer using Firefox 48.0.2 and when they click on a sender's name in an email, then select "Add Contact," the new contact window pops up; however, the Primary Email Address field is blank and should automatically fill. I have Firefox 58.0.2 on a Windows 10 machine and do not have this issue. I'm wondering if there is some sort of bug or compatibility issue between Firefox 48.0.2 and Smarter Mail 16.3.6628, which we just updated to recently. The customer did not have this issue before the update.