IR - if count (primary key) cannot change to count different column
Apex 4.1.1.00.23 Windows 7 IE8 / Firefox 16
If I add a Group By and Count to an Interactive report and choose the primary key column as the one to Count, run the report and then edit the Group By to count a different column, the result set does not change, and if I edit the Group By again it shows that the Counted column has reverted back to the primary key column.
If I initially choose a different column I can change it and rerun the report successfully, but once I choose the primary key column it cannot be changed. This seems to happen on all applications and all browsers. Is it a bug in Apex?
Thanks,
Nick.