Log in as admin Create 3 new users, all with identical surname Navigate to Reports > Report builder > Custom reports in site administration Create a new report using the Users report source, ensuring Include default setup is unchecked In report editor, open Settings > Sorting (so it's visible while editing) Add the following columns: User > Surname User > First name Confirm the Settings > Sorting area lists the following sortable columns Surname First name Set aggregation for First name column to Comma separated values Confirm First name is no longer listed in Settings > Sorting Set aggregation for First name column to Count Confirm First name is listed in Settings > Sorting Remove aggregation for First name column Confirm First name is still listed in Settings > Sorting