The created window contains a closing button, but clicking on it does not have
any effect. I will attach two source files from the awt examples in which such a
window is created. The relevant sourcecode is within the method "showTopWindow(
Rectangle _aRectangle)":

    // The Toolkit is the creator of all windows...
    Object oToolkit =
m_xMCF.createInstanceWithContext("com.sun.star.awt.Toolkit", m_xContext);
    XToolkit xToolkit = (XToolkit) UnoRuntime.queryInterface(XToolkit.class,
oToolkit);

    // set up a window description and create the window. A parent window is
always necessary for this...
    com.sun.star.awt.WindowDescriptor aWindowDescriptor = new
com.sun.star.awt.WindowDescriptor();
    // a TopWindow is contains a title bar and is able to inlude menus...
    aWindowDescriptor.Type = WindowClass.TOP; 
    // specify the position and height of the window on the parent window
    aWindowDescriptor.Bounds = _aRectangle;
    // set the window attributes...
    aWindowDescriptor.WindowAttributes = WindowAttribute.SHOW +
WindowAttribute.MOVEABLE + WindowAttribute.SIZEABLE + WindowAttribute.CLOSEABLE;
    
    // create the window...
    XWindowPeer xWindowPeer = xToolkit.createWindow(aWindowDescriptor);
    XWindow xWindow = (XWindow) UnoRuntime.queryInterface(XWindow.class,
xWindowPeer);

    // create a frame and initialize it with the created window...
    Object oFrame = m_xMCF.createInstanceWithContext("com.sun.star.frame.Frame",
m_xContext);
    m_xFrame = (XFrame) UnoRuntime.queryInterface(XFrame.class, oFrame);
    
    Object oDesktop =
m_xMCF.createInstanceWithContext("com.sun.star.frame.Desktop", m_xContext); 
    XFramesSupplier xFramesSupplier = (XFramesSupplier)
UnoRuntime.queryInterface(XFramesSupplier.class, oDesktop);
    m_xFrame.setCreator(xFramesSupplier);
    // get the XTopWindow interface..
    xTopWindow = (XTopWindow) UnoRuntime.queryInterface(XTopWindow.class, xWindow);