4teamwork/ftw.participation — pull request #11 by maethu (2013-08-02 15:48:48+00:00)
Title: Set roles field on invitation form to required if multiple roles is disabled

@jone

I tried http://developer.plone.org/forms/z3c.form.html#making-widgets-required-conditionally
but it did no work in my case (don't know why)

My workaround is --> WidgetValidatorDiscriminators for the field roles