void list_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            ListBoxEdit      listBoxEdit = (ListBoxEdit)sender;
            DependencyObject hitObject   = listBoxEdit.InputHitTest(e.GetPosition(listBoxEdit)) as DependencyObject;
            FrameworkElement hitItem     = LayoutHelper.FindParentObject <ListBoxEditItem>(hitObject);

            if (hitItem != null)
            {
                isDragStarted = true;
            }
        }