Trying eM client and one thing that would be nice

Been using Outlook for a little while now and one thing that has kept me doing so is the ease in which you can define an alias when sending an email. With Outlook you can send as an alias right at the point of creating then sending an email. I notice with eM client you need to predefine these aliases.

Could just do as Outlook does and offer an option to send with another email address ( alias )