Single Select Slicer with Calculation Group Items

Thanks Felix.

If I add a slicer with the calculation group as the field - it shows no selection controls in formatting to change it to single select.

If I change the field to something else - the option on formatting of selection controls and single select appears?

I have had a play with it - it would seem that if I use another field, choose single select then swop the field for the calaculation group then it is indeed single select.

This may be something to do with - when teh calculation group in in teh filter wells of the visual or page - it has a yellow box flagging as single select. Though you can multiselect on boteh the filters and the slicer? Is ita property of caluation group to be single select? Thanks for your help.