Hi Boris,

I split this thread so we can keep this issue separate and create a case for you.

I tried this out using the Insert method as you described and I am seeing the same exception. So this is a bug in the grid. I think what's happening here is that the e.SortedColumns collection is a cloned collection of cloned columns. And you are inserted a column from the real grid (so it's not a clone) and this is causing the issue. When you Add a column via the key, it works okay, because you are not passing in a non-cloned column object and the grid is smart enough to create a clone. When you Add a column object, the grid detects this and clones it for you. But it seems that the Insert method fails to do this - probably just an oversight.

That being the case, you can work around this by using the Add method instead of insert:

        private void ultraGrid1_BeforeSortChange(object sender, BeforeSortChangeEventArgs e)
        {
            var grid = (UltraGrid)sender;
            UltraGridColumn colOverdue = grid.DisplayLayout.Bands[0].Columns["Boolean 1"];

            if (colOverdue != null)
            {
                if (e.SortedColumns.IndexOf(colOverdue) < 0)
                {
                    List<UltraGridColumn> sortedColumns = new List<UltraGridColumn>(e.SortedColumns.Count + 1);
                    sortedColumns.Add(colOverdue);
                    foreach (UltraGridColumn sortedColumn in e.SortedColumns)
                    {
                        sortedColumns.Add(sortedColumn);
                    }
                    e.SortedColumns.Clear();

                    foreach (UltraGridColumn column in sortedColumns)
                        e.SortedColumns.Add(column, false);
                }
            }
        }