JLabel tooltip is not visible on top of BrowserView

I have this problem: tooltip of the label (JLabel) is hidden by a BrowserView. The tooltip properly shown top of any other java component, but gets hidden by BrowserView. What I want is to make the tooltip visible on top of BrowserView. Anyone knows the reason for it and a way to get the tooltip visible.

Resulted UI and how tooltip is hidden is attached here.

Code sample:

public class TestFrame
{
  public static void main (String args[])
  {

    JSplitPane splitPane = new JSplitPane();

    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    JPanel topPanel =  new JPanel();
    topPanel.setBorder(new LineBorder(Color.black));
    topPanel.setSize(75, 75);
    JLabel label = new JLabel("TestLabel");
    label.setToolTipText("Test Tooltip 1");
    topPanel.add(label);
    splitPane.setLeftComponent(topPanel);

    Browser browser = new Browser();
    BrowserView browserView = new BrowserView(browser);
    splitPane.setRightComponent(browserView);
    browser.loadURL("http://www.google.com");

    frame.add(splitPane);
    frame.setSize(700, 500);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}

Result UI: Right panel is a BrowserView which hides the Tooltip of left panel label

enter image description here