Currently the preview screen is available to users who can manage questionnaire activities or edit questions.

Imagine this situation (which occurs at the OU):

• one set of people, called course managers, create courses and so have the two capabilities above
• one set of people, called tutors, deliver courses to students, who can neither edit course activities nor submit quizzes or questionnaires
• one set of people, called students, take courses, who cannot edit course activities but who can submit quizzes and questionnaires.

Tutors have neither of the two capabilities above, nor questionnaire:submit. Students only have questionnaire:submit. Course managers have the two capabilities above, but not submit.

Students can see what's in the questionnaire straight away through the view tab. Course managers can also see it through the preview tab. But tutors haven't any idea of the questionnaire coverage until at least one student submits, and then they can see it through the responses tabs.

I propose adding a specific capability to control access to the preview tab. This would, by default, be given to the same people as questionnaire:manage and questionnaire:editquestions. We would then also be able to give it to tutors.