Hi there,

Here is the code that will allow you to enable multi-select rows (or cells):

private void ultraGrid1_InitializeLayout(object sender, Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs e)
        {

//Configure what happens when you click cells / rows

            e.Layout.Override.CellClickAction = Infragistics.Win.UltraWinGrid.CellClickAction.RowSelect;

//OR

           e.Layout.Override.CellClickAction = Infragistics.Win.UltraWinGrid.CellClickAction.CellSelect;

//Configure the "Multi-select" functionality
            e.Layout.Override.SelectTypeCell = Infragistics.Win.UltraWinGrid.SelectType.Extended;
            e.Layout.Override.SelectTypeRow = Infragistics.Win.UltraWinGrid.SelectType.Extended;

}