Bug with send from address when replying to a message

Bug with send from address when replying to a message

Hi, I've set up the Zoho Mail add-on for Zoho CRM. I want the default send from address to be milt@fivestarforklifttraining.com. This works well when I click on 'compose' in the emails section. However, when I open a contact and click send new email, it shows milton_bc@zoho.com as the default.

Is this a bug or am I missing a setting?