Nullreference exception on Treelistbox

Hi,

randomly I'm getting a nullreference exception when trying to click on treeitems. It happens after time so I don't know exactly how to reproduce it

System.NullReferenceException:
at ActiproSoftware.Windows.Controls.Grids.TreeListBoxItem.OnPointerPressed(Object sender, InputPointerButtonEventArgs e)
at ActiproSoftware.Windows.Input.InputAdapter.#doi(Object #xhb, InputEventArgs #yhb, InputPointerButtonKind #zYi)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
at System.Windows.Input.InputManager.ProcessStagingArea()
at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

 
When debugging at runtime with an external debugging software which disassembles the code (I hope this is oky for you) I found the line which seems to have a null references:

private void OnPointerPressed(object sender, InputPointerButtonEventArgs e)
{
if (e == null || e.Handled || !base.IsEnabled)
{
return;
}
[....]
TreeListBox owner = this.treeNode.Owner; <----- At this line an exception is thrown