Hello,

We are using Infragistics 2011 vol 1

The option of xamGrid GroupBySettings.GroupByOperation is set to GroupByOperation.MergeCells.

We have the following columns collection in xamGrid:

            TextColumn col1 = new TextColumn() { Key = "Col1", HeaderText = "Number" };
            TextColumn col2 = new TextColumn() { Key = "Col2", HeaderText = "Name" };
            TextColumn col3 = new TextColumn() { Key = "Col3", HeaderText = "LastName" };
            TextColumn col4 = new TextColumn() { Key = "Col4", HeaderText = "Adress" };
            TextColumn col5 = new TextColumn() { Key = "Col5", HeaderText = "Bool" };
            TextColumn col6 = new TextColumn() { Key = "Col6", HeaderText = "Balance" };
            GroupColumn col7 = new GroupColumn() { Key = "Col7", HeaderText = "EntityData" };
            col7.Columns.Add(col1);
            col7.Columns.Add(col2);
            col7.Columns.Add(col3);
            col7.Columns.Add(col4);
            col7.Columns.Add(col5);

            xamGrid1.Columns.Add(col7);
            xamGrid1.Columns.Add(col6);

When we add column to xamGrid.GroupByColumns column using visual interface all is ok. But when we try to remove the column from that collection, we get the OutOfRangeExpection:

Имя параметра: index
   в System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   в System.ThrowHelper.ThrowArgumentOutOfRangeException()
   в System.Collections.Generic.List`1.get_Item(Int32 index)
   в System.Collections.ObjectModel.Collection`1.get_Item(Int32 index)
   в Infragistics.Controls.Grids.ColumnBaseCollection.RemoveItem(Int32 index)
   в Infragistics.Collections.CollectionBase`1.Remove(T item)
   в Infragistics.Controls.Grids.Column.SetGroupBy(Boolean groupBy)
   в Infragistics.Controls.Grids.GroupByColumnsCollection.RemoveItem(Int32 index)
   в Infragistics.Collections.CollectionBase`1.Remove(T item)
   в Infragistics.Controls.Grids.Column.set_IsGroupBy(Boolean value)
   в Infragistics.Controls.Grids.Primitives.RemoveGroupByColumnCommand.ExecuteCommand(Column col)
   в Infragistics.Controls.Grids.ColumnCommandBase.Execute(Object parameter)
   в Infragistics.Controls.CommandSource.Execute(ICommandTarget target, Boolean canExecute)
   в Infragistics.Controls.CommandSource.LookForCommandTarget(FrameworkElement parent, Boolean execute, ICommand command)
   в Infragistics.Controls.CommandSource.InvokeCommand(Boolean execute)
   в Infragistics.Controls.CommandSource.EventFired(Object sender, EventArgs e)
   в System.Windows.Controls.Primitives.ButtonBase.OnClick()
   в System.Windows.Controls.Button.OnClick()
   в System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
   в System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
   в MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)

In this example we get that error only with 2 columns: col4 (Adress) and col5 (Bool).