silverstripe/sapphire — pull request #709 by dd1079 (2012-08-07 16:13:07+00:00)
Title: FIX: Proper buttonset styling

Buttons inside buttonsets now have a -1px margin left to avoid duplicate borders and the buttensate compensates for the offset with a margin-left: 1px – this also does solve the issue of the missing left border because of the Action's overflow: hidden.