Problem with expanding custom control based on TreeView

Hi. I'm using custom control for custom class that I add to PropertyGrid.ItemsSource. This control is based on wpfs TreeView. But I have faced with problem: there no expanding tree when I try to do this. In output appears next message:

System.Windows.Data Error: 8 : Cannot save value from target back to source. BindingExpression:Path=IsExpanded; DataItem='TreeViewItem' (Name=''); target element is 'ToggleButton' (Name='Expander'); target property is 'IsChecked' (type 'Nullable`1') InvalidCastException:'System.InvalidCastException: Не удалось привести тип объекта "System.String" к типу "Mindscape.WpfElements.WpfPropertyGrid.PropertyGridRow".
в Mindscape.WpfElements.PropertyGrid.#2V(Object sender, RoutedEventArgs e)
в System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
в System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
в System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
в System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
в System.Windows.Controls.TreeViewItem.OnExpanded(RoutedEventArgs e)
в System.Windows.Controls.TreeViewItem.OnIsExpandedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
в System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
в System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
в System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
в System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
в System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
в System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
в MS.Internal.Data.PropertyPathWorker.SetValue(Object item, Object value)
в MS.Internal.Data.ClrBindingWorker.UpdateValue(Object value)
в System.Windows.Data.BindingExpression.UpdateSource(Object value)'

I've developed some sample that demonstrate this problem: http://www.2shared.com/file/h-jzlMGI/ProrertyGrid__TreeViewProblemS.html

Just to run this solution and try to expand the tree.

Can I get the ordinary behavior in this context.

P.S. Sorry about my English

This occurs because the property grid listens for bubbling Expanded and Collapsed events from its internal tree view items.  Your tree view items are also raising Expanded and Collapsed events, and these are bubbling up to the property grid which thinks they are its own and tries to act on them.

To work around this, just add event handlers in your user control to stop the Expanded and Collapsed events bubbling outside the user control.  In the LinkEditor constructor, add the following lines:

      xmlTreeView.AddHandler(TreeViewItem.ExpandedEvent, new RoutedEventHandler(StopBubbling));
      xmlTreeView.AddHandler(TreeViewItem.CollapsedEvent, new RoutedEventHandler(StopBubbling));

And implement the StopBubbling method to basically do nothing:

      private void StopBubbling(object sender, RoutedEventArgs e)
      {
        e.Handled = true;
      }

Thank you  for reply and help, Ivan.