Hello – First of all, thank you for developing this high quality email client. It has been wonderful to use.
My one feature request: Make it easy to copy the email address of the contact, in the sidebar. You could do this by adding a simple “copy” button. Ideally, it would be where I’ve highlighted in yellow in the screenshot below.
This would make my life so much easier – especially for customer service emails, where I usually have to copy the email address so I can look it up in another system.