It also happens that I didn't read carefully the documentation about formgroup, in particular the fact that if you use cols as a parameter in the tag, it behaves like the grid tag. So I used that and some custom stuff to make sure I display the section name from the template itself but I used a template from acs-templating/resources/forms/ instead so I can re-use it for several forms.
I tried to use the cols attribute on a formgroups tag in the standard.adp template in acs-templating/resources/forms but I get an error @formgroup.widget@ not found or something like that. If I remove that piece, I get another one complaining that it can't find @formgroup.option@.