When draft is sent it should be removed from draft folder

[marbetschar]

What Happened

When I edit a draft and hit the send button, the mail gets sent to the recipient and copied to the Sent folder. But the original draft is still stored in the Drafts folder (without the latest changes done just before sending it).

Expected Behavior

Whenever I send a draft, I'd expect it to be removed from the Drafts folder.