Hotpot (plugin)

Moodle documentation on Hotpot reports for 2.2 (we are using 2.2.3) seems to indicate that we should have a dropdown to select by group – we do have a Filter area at the top, but that doesn’t seem to have the option to select by group – in 1.9 our staff had a Report section across the top with a dropdown showing the default All users, but on dropping down it listed all the students names, but at the top of the list each one of the Groups set in the course was available.  We seem to have a Filter in 2.2.3 - User full name; grade; time; duration; status; and rawscore - I have tried putting the group name in full name, but that has no effect – but then adding any student’s fore-,  surname or full name to the User full name in the Filter also has no effect!  The groups are set up fine within the course and the HotPot has ‘Separate groups’ selected in the Settings.  Can anyone shed any light for me?