Inside tab scroll not work

Hello,
I am new in Vaadin.

I try to create tab with scrollable internal content but without result - scroll work only in parent split panel.
When I scroll down tabs move up and become unvisible.

@Override
    public void init() {
        String bigContent = "";
        for (int i = 0; i < 10000; i++) {
            bigContent += "word ";
        }

        TabSheet tabSheet = new TabSheet();

        Panel tab1 = new Panel();
        tab1.addComponent(new Label(bigContent));
        tabSheet.addTab(tab1, "Tab 1", null);

        Panel tab2 = new Panel();
        tab2.addComponent(new Button("button"));
        tabSheet.addTab(tab2, "Tab 2", null);

        SplitPanel horizontalSplit = new SplitPanel(SplitPanel.ORIENTATION_HORIZONTAL);
        horizontalSplit.setFirstComponent(new Label("Navigation"));
        horizontalSplit.setSecondComponent(tabSheet);

        setMainWindow(new Window("Tab Test"));
        getMainWindow().setContent(horizontalSplit);

        //buildMainLayout();
    }

Could you advice please what to do, I already try different methods (setHeight("90%"), setSizeFull, setSizeUndefined, setScrolable() with true and false for different components, use special around Panel - nothing help). Browser Firefox 3.5.9, Vaadin 6.2.0. I try to find answer in formut but can not.

Update1. If I place label to Panel and set it height for example 200px it work but it is NOT I NEED, I need not 200px but 100% and this not work.