Create a course and add a survey of type COLLES (Preferred) . Create two student users and enrol them in the course. Login as one of the students and answer the survey. Please make sure to select an answer to the question " How long did this survey take you to complete? ". Remember the option you selected. Now login as the other student and answer the survey too, but this time don't select anything in the time question. Login as teacher and go to survey results. In there click the "Participants" option and select the first student. Check that there's no ">" character in the left of the first graphic and that the answer to the time question is the one you selected (and not just a number). Now select the other student. Check that there's no ">" character in the left of the first graphic and that there's no answer to the time question since you didn't select anything.