Set secondary account SMTP as default sending address?

I have a secondary email provider set up in order to be used as my main SMTP server. In the Compose window that sent from address is shown in the drop down. How do I set that email account address as the default “sent from” to always show by default when composing and sending messages?

Perhaps you need to go to Menu > Accounts, select the account and click on “Set as default” on top menu and click on “Save & Close”.

It needs IMAP activated as well in order to nominate a default account. I don’t want that. I was hoping to be able to just find a way to have the secondary account address to show up as the default SMTP server in the compose dropdown.