Log in as an editing teacher in a course. Enrol several students in the course. Create a feedback activity with the following setting: Record user names: User's name will be logged and shown with answers Add at least one question. Click the "Show non-respondents" tab. Toggling checked states of items via the master checkbox Tick the checkbox in the select column header on the table containing the list of non-respondents. Confirm that the checkboxes for each participant in the non-respondent list are checked. Untick the checkbox in the select column header. Confirm that the checkboxes for each participant in the non-respondent list become unchecked. Ticking the item checkboxes Tick the master checkbox to select all the non-respondents. Untick one of the non-respondents Confirm that the master checkbox gets unticked. Tick the non-respondent that was deselected earlier so that all non-respondents are now all selected again. Confirm that the master checkbox gets ticked.