// ------------------------- 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();
}