Blink of expandable items on editable items collection change

Hi,

I use property grid with editable collection of expandable items. When i add new item to collection existing expandable items blink.

Here is sample code:

<Window x:Class="ActiProTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:propgrid="clr-namespace:ActiproSoftware.Windows.Controls.PropertyGrid;assembly=ActiproSoftware.PropertyGrid.Wpf"
xmlns:propgridPrimitives="clr-namespace:ActiproSoftware.Windows.Controls.PropertyGrid.Primitives;assembly=ActiproSoftware.PropertyGrid.Wpf"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<Style TargetType="{x:Type propgridPrimitives:PropertyGridDataAccessorItem}">
<Setter Property="IsExpanded" Value="True"/>
</Style>
</Window.Resources>
<propgrid:PropertyGrid x:Name="propGrid" SelectedObject="{Binding}" CollectionDisplayMode="EditableInline"/>
</Window>

[TypeConverter(typeof(ExpandableObjectConverter))]
public class ExpandableItem
{
  public String Name { get; set; }
  public bool Visible { get; set; } 

  public ExpandableItem()
  {
    Name = "New Item";
    Visible = true;
   }
}
	
public class DataContext
{
  private ObservableCollection<ExpandableItem> _items; 

  public ObservableCollection<ExpandableItem> Items
  {
	get
	{
          return _items ?? (_items = new ObservableCollection<ExpandableItem>
	  {
		new ExpandableItem()
	        {
		  Name = "John",
		  Visible = true
		},
		new ExpandableItem()
		{
		  Name = "Silver",
		  Visible = true
		},
	        });
	   }
	}
   }
 
public partial class MainWindow : Window
{
  public MainWindow()
  {
    InitializeComponent();
    DataContext = new DataContext();
  }
}

Thanks