New Post: Editable combobox problem

<Window x:Class="WpfApplication40.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApplication40"
        xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit"
        xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"
        xmlns:sys="clr-namespace:System;assembly=mscorlib"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
   <Window.Resources>
      <ObjectDataProvider MethodName="GetValues"
                          ObjectType="{x:Type sys:Enum}"
                          x:Key="CombboStylesValues">
         <ObjectDataProvider.MethodParameters>
            <x:Type TypeName="local:ComboValues" />
         </ObjectDataProvider.MethodParameters>
      </ObjectDataProvider>
   </Window.Resources>
    <StackPanel>
      <xcdg:DataGridControl x:Name="_dataGrid"
                            ItemsSource="{Binding MyList}">
         <xcdg:DataGridControl.Columns>
            <xcdg:Column FieldName="Name"/>
            <xcdg:Column FieldName="FlangeType"
                         Title="Flange Type"
                         Width="80">

               <xcdg:Column.CellEditor>
                  <xcdg:CellEditor>
                     <xcdg:CellEditor.EditTemplate>
                        <DataTemplate>
                           <ComboBox ItemsSource="{Binding Source={StaticResource CombboStylesValues}}"
                                     SelectedValue="{xcdg:CellEditorBinding}"
                                     IsEditable="True"/>
                        </DataTemplate>
                     </xcdg:CellEditor.EditTemplate>
                  </xcdg:CellEditor>
               </xcdg:Column.CellEditor>
            </xcdg:Column>
         </xcdg:DataGridControl.Columns>
      </xcdg:DataGridControl>
   </StackPanel>
</Window>

 public enum ComboValues
  {
    One,
    Two,
    Three,
    Four
  }

  public partial class MainWindow : Window
  {
    public MainWindow()
    {
      Xceed.Wpf.Toolkit.Licenser.LicenseKey = "XXXXX-XXXXX-XXXXX-XXXX";

      InitializeComponent();

      this.DataContext = this;

      this.MyList = new List<MyClass>()
      {
        new MyClass() { Name = "First", FlangeType = ComboValues.One },
        new MyClass() { Name = "Second", FlangeType = ComboValues.Three},
        new MyClass() { Name = "Third", FlangeType = ComboValues.Four }
      };
    }
   
    public List<MyClass> MyList
    {
      get;
      set;
    }
  }

  public class MyClass
  {
    public string Name
    {
      get;
      set;
    }

    public ComboValues FlangeType
    {
      get;
      set;
    }
  }