When responding to an e-mail from within Sugar (clicking on 'Reply' in the e-mail's detail view) the response is merged into the original on top. Like a e-mail client would do, including putting the headers in between the original and the response:
> From: Someone
> Date Sent: 02.03.2016 14:08
> To: Some Guy
> Subject: Hello world
This happens with Sugar 18.104.22.168. With Sugar 6.5 separate e-mails where created for every sent or received e-mail. Is there a way to go back to that system?