public MouseGrabber() 
{
            MenuSelectionManager msm = MenuSelectionManager.defaultManager();
            msm.addChangeListener(this);
            this.lastPathSelected = msm.getSelectedPath();
            if(this.lastPathSelected.length != 0) {
                grabWindow(this.lastPathSelected);
            }
}

  void cancelPopupMenu() 
{
            // We should ungrab window if a user code throws
            // an unexpected runtime exception. See 6495920.
            try {
                // 4234793: This action should call firePopupMenuCanceled but it's
                // a protected method. The real solution could be to make
                // firePopupMenuCanceled public and call it directly.
                List popups = getPopups();
                Iterator iter = popups.iterator();
                while (iter.hasNext()) {
                    JPopupMenu popup = (JPopupMenu) iter.next();
                    popup.putClientProperty("JPopupMenu.firePopupMenuCanceled", Boolean.TRUE);
                }
                MenuSelectionManager.defaultManager().clearSelectedPath();
            } catch (RuntimeException ex) {
                realUngrabWindow();
                throw ex;
            } catch (Error err) {
                realUngrabWindow();
                throw err;
            }
}

 public  void componentHidden(ComponentEvent e) 
{
            cancelPopupMenu();
}

 public  void componentMoved(ComponentEvent e) 
{
            cancelPopupMenu();
}

 public  void componentResized(ComponentEvent e) 
{
            cancelPopupMenu();
}

 public  void componentShown(ComponentEvent e) 
{
            cancelPopupMenu();
}

 public  void eventDispatched(AWTEvent ev) 
{
            if(ev instanceof sun.awt.UngrabEvent) {
                // Popup should be canceled in case of ungrab event
                cancelPopupMenu( );
                return;
            }
            if (!(ev instanceof MouseEvent)) {
                // We are interested in MouseEvents only
                return;
            }
            MouseEvent me = (MouseEvent) ev;
            Component src = me.getComponent();
            switch (me.getID()) {
            case MouseEvent.MOUSE_PRESSED:
                if (isInPopup(src) ||
                    (src instanceof JMenu && ((JMenu)src).isSelected())) {
                    return;
                }
                if (!(src instanceof JComponent) ||
                   ! (((JComponent)src).getClientProperty("doNotCancelPopup")
                         == BasicComboBoxUI.HIDE_POPUP_KEY)) {
                    // Cancel popup only if this property was not set.
                    // If this property is set to TRUE component wants
                    // to deal with this event by himself.
                    cancelPopupMenu();
                    // Ask UIManager about should we consume event that closes
                    // popup. This made to match native apps behaviour.
                    boolean consumeEvent =
                        UIManager.getBoolean("PopupMenu.consumeEventOnClose");
                    // Consume the event so that normal processing stops.
                    if(consumeEvent && !(src instanceof MenuElement)) {
                        me.consume();
                    }
                }
                break;
            case MouseEvent.MOUSE_RELEASED:
                if(!(src instanceof MenuElement)) {
                    // Do not forward event to MSM, let component handle it
                    if (isInPopup(src)) {
                        break;
                    }
                }
                if(src instanceof JMenu || !(src instanceof JMenuItem)) {
                    MenuSelectionManager.defaultManager().
                        processMouseEvent(me);
                }
                break;
            case MouseEvent.MOUSE_DRAGGED:
                if(!(src instanceof MenuElement)) {
                    // For the MOUSE_DRAGGED event the src is
                    // the Component in which mouse button was pressed.
                    // If the src is in popupMenu,
                    // do not forward event to MSM, let component handle it.
                    if (isInPopup(src)) {
                        break;
                    }
                }
                MenuSelectionManager.defaultManager().
                    processMouseEvent(me);
                break;
            case MouseEvent.MOUSE_WHEEL:
                if (isInPopup(src)) {
                    return;
                }
                cancelPopupMenu();
                break;
            }
}

  void grabWindow(MenuElement[] newPath) 
{
            // A grab needs to be added
            final Toolkit tk = Toolkit.getDefaultToolkit();
            java.security.AccessController.doPrivileged(
                new java.security.PrivilegedAction() {
                    public Object run() {
                        tk.addAWTEventListener(MouseGrabber.this,
                                AWTEvent.MOUSE_EVENT_MASK |
                                AWTEvent.MOUSE_MOTION_EVENT_MASK |
                                AWTEvent.MOUSE_WHEEL_EVENT_MASK |
                                AWTEvent.WINDOW_EVENT_MASK | sun.awt.SunToolkit.GRAB_EVENT_MASK);
                        return null;
                    }
                }
            );
            Component invoker = newPath[0].getComponent();
            if (invoker instanceof JPopupMenu) {
                invoker = ((JPopupMenu)invoker).getInvoker();
            }
            grabbedWindow = invoker instanceof Window?
                    (Window)invoker :
                    SwingUtilities.getWindowAncestor(invoker);
            if(grabbedWindow != null) {
                if(tk instanceof sun.awt.SunToolkit) {
                    ((sun.awt.SunToolkit)tk).grab(grabbedWindow);
                } else {
                    grabbedWindow.addComponentListener(this);
                    grabbedWindow.addWindowListener(this);
                }
            }
}

 boolean isInPopup(Component src) 
{
            for (Component c=src; c!=null; c=c.getParent()) {
                if (c instanceof Applet || c instanceof Window) {
                    break;
                } else if (c instanceof JPopupMenu) {
                    return true;
                }
            }
            return false;
}

  void realUngrabWindow() 
{
            Toolkit tk = Toolkit.getDefaultToolkit();
            if(grabbedWindow != null) {
                if(tk instanceof sun.awt.SunToolkit) {
                    ((sun.awt.SunToolkit)tk).ungrab(grabbedWindow);
                } else {
                    grabbedWindow.removeComponentListener(this);
                    grabbedWindow.removeWindowListener(this);
                }
                grabbedWindow = null;
            }
}

 public  void stateChanged(ChangeEvent e) 
{
            MenuSelectionManager msm = MenuSelectionManager.defaultManager();
            MenuElement[] p = msm.getSelectedPath();
            if (lastPathSelected.length == 0 && p.length != 0) {
                grabWindow(p);
            }
            if (lastPathSelected.length != 0 && p.length == 0) {
                ungrabWindow();
            }
            lastPathSelected = p;
}

  void ungrabWindow() 
{
            final Toolkit tk = Toolkit.getDefaultToolkit();
            // The grab should be removed
             java.security.AccessController.doPrivileged(
                new java.security.PrivilegedAction() {
                    public Object run() {
                        tk.removeAWTEventListener(MouseGrabber.this);
                        return null;
                    }
                }
            );
            realUngrabWindow();
}

  void uninstall() 
{
            synchronized (MOUSE_GRABBER_KEY) {
                MenuSelectionManager.defaultManager().removeChangeListener(this);
                ungrabWindow();
                AppContext.getAppContext().remove(MOUSE_GRABBER_KEY);
            }
}

 public  void windowActivated(WindowEvent e) 
{

}

 public  void windowClosed(WindowEvent e) 
{
            cancelPopupMenu();
}

 public  void windowClosing(WindowEvent e) 
{
            cancelPopupMenu();
}

 public  void windowDeactivated(WindowEvent e) 
{
            cancelPopupMenu();
}

 public  void windowDeiconified(WindowEvent e) 
{

}

 public  void windowIconified(WindowEvent e) 
{
            cancelPopupMenu();
}

 public  void windowOpened(WindowEvent e) 
{

}