anchor.diff:    begin
       currentCoord := '';
       tmpIndex := FVerticalKeysIndex;
  -    parentKeyValue := '';
  +    parentKeyValue := EMPTY_STRING_VALUE;
       for k := 0 to FVerticalGroupByDefs.Count -1 do
       begin
         tmpValue := FDataProvider.GetDatum(i).GetPropertyByFieldName(FVerticalGroupByDefs.Get(k).FieldName);
  
positive.code:   FFieldName:= aSource.FieldName;
    FDataType := aSource.DataType;
    FOperationKind := aSource.OperationKind;
    FFormula := aSource.Formula;
  end;
  
  class function TmGroupByDef.CheckOperationKindCompatibility(const aOperationKind: TmGroupByOperationKind; const aDataType: TFieldType): boolean;
  
negative.code: //  gpoDistinct, gpoDateYear, gpoDateMonth, gpoDateTheMonth, gpoDateDay, gpoDateTheDay, gpoDateQuarter, gpoDateTheQuarter, gpoFirstLetter, goFormula
  end;
  
  end.
  