Sorting order in Report Studio 10 doesn’t work properly

[leon]

Greeting All,
The task is to reproduce the missed sorting order to the report migrated from Cognos 8 to Cognos 10. Seems very straight forward: in 8 sorting in most cases works on 3 columns grouped by other column without visible setting signs. In Cognos 10 doing everything by the book: in 'Edit layout sorting' specifying ascending sorting fields within grouped column (drugging into the folder).  No reactions. Tried to sort within different grouped columns (which in my case should be the same), but it seems no affect.
I am not an expert in development and could miss something even actual task appears very simple.
Please help if you have an idea.
Appreciated in advance,

   Leon