Compose new message in same window

Would it be possible to have the compose message window simply appear in the main window similar to when you read email when the reading pane is off?

(Originally posted by superDuperCyberTechno on GitHub.)

Hey! This would be pretty cool - I’m hoping to get a plugin distribution system in to the app this year and I think this would make a great plugin. Will see what we can do :+1:

(Originally posted by bengotow on GitHub.)