pressing Escape or Save while composing an email results in data loss
Pressing Escape while the composing window is open closes the window without saving or offering to save the message as a draft. As a Vim user I am in a habit of hitting Escape when I'm done typing, and twice since I've started using Geary I have finished composing an email, hit Escape, and then lost the whole thing and needed to start over. When the user closes the composing window, Geary should either prompt the user to save the message or do so automatically.
Update: While rewriting the email I had lost just now, I hit the "Save and Close" button in the header bar, hoping to save my message as a draft and avoid accidentally losing work again. Unfortunately, the "Save and Close" button seems to actually be a "Close and Discard without Warning" button, because the message was not saved as a draft. To make sure I wasn't going insane, I replicated the behavior with a new message. Indeed, the message just gets discarded, not saved.