HELP with HightCharts

[Vladimir]

hello ,

I tried to add a chart to TabSet.

When I add a chart on the first Tab, the chart is work.
But when I try to add a chart on the other Tab, I get this error :

Uncaught JavaScript exception [uncaught exception: java.lang.AssertionError: A widget that has an existing parent widget may not be added to the detach list] in , line 0

please some one have an idea how to fix this ?? (I use SmartGWT 2.5)

code
public class PhSh implements EntryPoint {
public void onModuleLoad() {
RootPanel rootPanel = RootPanel.get();

    Canvas canvas = new Canvas();
    canvas.setSize("376px", "249px");
    rootPanel.add(canvas, 10, 10);

    TabSet tabSet = new TabSet();
    tabSet.setSize("379px", "249px");

    Tab tab = new Tab("newTab");

    HLayout hLayout = new HLayout();

    //Canvas canvas_1 = new Canvas();
    Chart chart1 = new Chart();
    //canvas_1.addChild(chart1);
    hLayout.addMember(chart1);
    tab.setPane(hLayout);
    tabSet.addTab(tab);

    Tab tab_1 = new Tab("newTab");

    HLayout hLayout_1 = new HLayout();
    Chart chart = new Chart();
    hLayout_1.addMember(chart);
    tab_1.setPane(hLayout_1);
    tabSet.addTab(tab_1);
    rootPanel.add(tabSet, 11, 11);
}

}

thanks!!!