sorting with textgridsss2 csvcolumn

Hi all!
we do have a problem here with sorting in textgridsss2 csvcolumns
clicking on the little sort icon fort the first time produces the expected sort, all other clicks on the sort icon in other columns are ignored.
this seems to be a new ‘feature’ in version 4.0.
in versin 2.5 everything was fine
have fun
achim