I'm very deappointed with your D&D editor.
Too basic and too simple : cant customize mail width, cant set left or right margins between blocs, cant do the same with images, etc, etc...
See what Maylstiler is able to do and please do the same with your aditor
Till then, i resume using Acymailig 5 or HTML , using the site editor or full HTML coming from another mail deign application.
Hope you will improve
Regards,
Phil