Hi there,
I need some help with ToolButtons and ContentPanel. I have a ContentPanel that has two sub ContentPanel. I need to collapse the external ContentPanel and the north ContentPanel, and I want to collapse the external ContentPanel using a ToolButton added in the header of the sub north ContentPanel (in this way I can hide the external ContentPanel header). My problem is that when I collapse the north ContentPanel the ToolButton I added disappears(so I can't collapse the external ContentPanel). How can I keep my ToolButton visible?
Here is what I've done...

Code:
ContentPanel panel;
    
    ContentPanel north = null;
    ContentPanel center = null;
    
    public SomethingToShow() {
        
        panel = new ContentPanel();    
        panel.setLayout(new BorderLayout());
        panel.setHeaderVisible(false);
        
        north = new  ContentPanel();
        center = new  ContentPanel();
        
        //North
        final BorderLayoutData northData = new BorderLayoutData(LayoutRegion.NORTH);  
        northData.setCollapsible(true);
        Header header = north.getHeader();
        
        //This button collapse the parent ContentPanel
         ToolButton collapseMainPanel = new ToolButton("x-tool-left");
         header.addTool(collapseMainPanel);
         collapseMainPanel.addSelectionListener(new SelectionListener<IconButtonEvent>() {

            public void componentSelected(IconButtonEvent ce) {
                panel.collapse();
            }
        }
        );
        panel.add(north, northData);
        
        //South
        BorderLayoutData centerData = new BorderLayoutData(LayoutRegion.CENTER);         
        panel.add(center, centerData);
        
    }
Thanks in advance!