Adding a "label" parameter to templates :
For each template (group of subtemplates) add a label parameter like so
bigfoot_content:
templates:
page:
block_sidebar:
*label: 'Blocks and Sidebar !'*
class: 'Seh\Bundle\SehBundle\Entity\Page\Template\BlockSidebar'
sub_templates:
block_sidebar_left: 'Left sidebar'
block_sidebar_right: 'Right sidebar'
This label will be displayed as a title for the group of children subtemplates when displayed.