OK, will try again with attachment upload (apparently size was to large--you have a pretty small limit for these days).  If you do not get it again, please send me an email to which I can reply with the attachment.

To reproduce, populate a grid with a data table with 3 or more columns  that have more than a couple unique values in the data for each column. As you originally suggested, set the InitializeGroupByRow event to e.Row.Fixed = true.  On loading the data, I am adding two columns to the groupby box in code, but the problem also occurs if you manually add them. 

After adding, the original group by population is correct.  Now, reverse the columns (move the right-most to the left-most, and the groupby is wrong.

In the images sent, see the original which shows the first node expanded to show there are multiple values (all the base nodes have 1 or more three possible sub-node values). Then the regroup image shows only one main node  and not the three possible values. 

Note my node values are all strings.

Here is how I am populating:

                ugCalcs.DisplayLayout.Override.GroupByRowDescriptionMask = "[value] ([count] [count,items,item,items])";
                ugCalcs.BeginUpdate();
                  if (ugCalcs.DataSource.IsNull() == false)
                {
                    ugCalcs.DisplayLayout.Override.AllowRowFiltering = Infragistics.Win.DefaultableBoolean.False;
                    ugCalcs.DisplayLayout.Bands[0].ClearGroupByColumns();
                    ugCalcs.DataSource = null;
                }
                ugCalcs.DataSource = _mainform.RefDat.DAL.ExecuteProcedure("PlanCalcList");
                ugCalcs.DisplayLayout.Override.AllowRowFiltering = Infragistics.Win.DefaultableBoolean.True;
                ugCalcs.DisplayLayout.ViewStyleBand = Infragistics.Win.UltraWinGrid.ViewStyleBand.OutlookGroupBy;
                ugCalcs.DisplayLayout.Bands[0].SortedColumns.Add("TranCat", false, true);
                ugCalcs.DisplayLayout.Bands[0].SortedColumns.Add("CalcCompare", false, true);

and then:

private void ugCalcs_InitializeGroupByRow(object sender, Infragistics.Win.UltraWinGrid.InitializeGroupByRowEventArgs e)
        {
            try
            {
              
               e.Row.Fixed = true;
            }
            catch (System.Exception)
            {
                //ignore
            }
        }

Hello sunibla,

I do not see an attachment here. Could you please try to attach the images again with the needed steps to reproduce this issue. Thank you in advance.

I finally got around to this and your suggestion fixes the rows, however, there are some weird behaviors and the grid does not seem to handle this correctly.  For instance, repositioning group columns or inserting new groupby columns before existing ones does not re-group the rows correctly. Adding new columns also causes related problem of grouping. When expanding some of the grouped rows, some of the other grouped rows disappear. 

See attached images in word doc to see problem.

Thanks.