// -------------------------- StopAnnotations -------------------------
/// <summary>
///   Disables annotations processing and hides annotations.</summary>
public void StopAnnotations()
{
    // If the AnnotationStore is active, flush and close it.
    if ( (_annotService != null) && _annotService.IsEnabled )
    {
        _annotService.Store.Flush();
        _annotStream.Flush();
        _annotStream.Close();
    }

    // If the AnnotationService is active, shut it down.
    if (_annotService != null)
    {
        if (_annotService.IsEnabled)
            _annotService.Disable();
        _annotService = null;
    }
}// end:StopAnnotations()

// ------------------------- DeleteMark_Click -------------------------
void DeleteMark_Click(object sender, RoutedEventArgs e)
{
    Annotation ann = ((MenuItem)sender).Tag as Annotation;
    _annStore.DeleteAnnotation(ann.Id);
    _annStore.Flush();

    MenuItem thisMenu = sender as MenuItem;
    ContextMenu parentMenu = thisMenu.Parent as ContextMenu;
    FrameworkElement dObj =
        parentMenu.PlacementTarget as FrameworkElement;
    while (!(dObj is StackPanel))
    {
        dObj = dObj.Parent as FrameworkElement;
    }

    ListBox collection = dObj.Parent as ListBox;
    collection.Items.Remove(dObj);
    Util.FlushDispatcher();
}