A SWT/RCP/JFace MenuManager subclass which stays open when one of its MenuItems is clicked

StayOpenMenuManager.java

import java.lang.reflect.Field;

import org.eclipse.jface.action.MenuManager;
import org.eclipse.swt.events.MenuDetectEvent;
import org.eclipse.swt.events.MenuDetectListener;
import org.eclipse.swt.events.MenuEvent;
import org.eclipse.swt.events.MenuListener;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;

public class StayOpenMenuManager extends MenuManager
{
    private Point point;

    @Override
    public Menu createContextMenu( Control parent )
    {
        final Menu menu = super.createContextMenu( parent );
    
        // add a listener to remember the position of the menu when it is created
        parent.addMenuDetectListener( new MenuDetectListener( )
        {
            public void menuDetected( MenuDetectEvent e )
            {
                point = new Point( e.x, e.y );
            }
        } );
        
        // add a listener to set the menu "hasLocation" field to false
        // when it closes so that it pops up under the mouse the next
        // time it is opened
        menu.addMenuListener( new MenuListener( )
        {
            @Override
            public void menuHidden( MenuEvent event )
            {
                try
                {
                    Field field = Menu.class.getDeclaredField( "hasLocation" );
                    field.setAccessible( true );
                    field.set( menu, false );
                }
                catch ( Exception e )
                {
                    e.printStackTrace();
                }
            }

            // whenever the menu is shown, add listeners to all the menu items
            // which re-show the menu when an item is selected
            // the only way to close the menu is to click outside of it
            @Override
            public void menuShown( MenuEvent event )
            {
                for ( MenuItem item : menu.getItems( ) )
                {
                    item.addSelectionListener( new SelectionListener( )
                    {
                        @Override
                        public void widgetSelected( SelectionEvent e )
                        {
                            Display.getDefault( ).asyncExec( new Runnable( )
                            {
                                @Override
                                public void run( )
                                {
                                    menu.setLocation( point );
                                    menu.setVisible( true );
                                }
                            } );
                        }

                        @Override
                        public void widgetDefaultSelected( SelectionEvent e )
                        {
                        }
                    });
                }
            }
        });
        
        return menu;
    }
}