protected override void Render(HtmlTextWriter writer)
        {
            writer.WriteLine("<div class='multiselect-dropdown{0}'>".FormatWith(CssClass.WithPrefix(" ")));

            ContainerPanel.RenderBeginTag(writer);

            ToolBox.RenderControl(writer);

            writer.WriteLine("<div class='items-list' >");
            base.Render(writer);
            writer.WriteLine("</div>");

            SelectedItemsPanel.RenderControl(writer);
            ContainerPanel.RenderEndTag(writer);

            SearchBox.RenderControl(writer);
            ViewBox.RenderControl(writer);

            writer.WriteLine("</div>");
        }