ZK - Open Source Ajax Java Framework

    ...
        // you must search for the correct 'onRightClick' writing 
   item.addEventListener("onClick", new myItemClickEventListener());
      
   ...

   /*inner Class
   public class myItemClickEventListener() implements org.zkoss.zk.ui.event.EventListener {
     public void onEvent(Event event) throws UiException {
        try {
          doSomething // here you can write the logic for your popup
          }
        catch (Exception e) {
          }}}

fileLabel.addEventListener("onRightClick", new EventListener() {
	public void onEvent(Event event) throws Exception {
		Menupopup popup = new Menupopup();
		Menuitem iDownload = new Menuitem("iDownload");
		iDownload.setLabel("Download");
		iDownload.setImage("/inc/download.png");
		iDownload.addEventListener("onClick", new EventListener() {
			public void onEvent(Event event) throws Exception {
				Filedownload.save(file.get_path(), null);
			}
		});
		iDownload.setParent(popup);
		// for testing purposes right now, I'm only trying this one
	}
});

public class View extends AppWindow {
    private static final long serialVersionUID = -5982827231487794662L;

    // Form Fields
    final private Listbox           _viewListBox     = new Listbox();
    final private Menupopup         _viewListBoxContextMenu     = new Menupopup();
    final private Menuitem	    _changeLocationMenuItem = new Menuitem("Change Location");

    public View(Component parent) {
        super(parent);

        this.setId(java.util.UUID.randomUUID().toString());
        this.setTitle("View");
        this.setClosable(true);
        try {
            this.setMode("overlapped");
        } catch (InterruptedException ex) {
        }

        _controller = new Controller(this);
    }

    @Override
    public void initialize(Component comp, Map<String,Object> params) {
        // Call Base Class Initialization.
        super.initialize(comp, params);

        Groupbox gpBox = new Groupbox();
        gpBox.setClosable(false);
        gpBox.appendChild(new Caption("Location"));
        gpBox.setParent(this);

        _viewListBoxContextMenu.setParent(gpBox);
        _changeLocationMenuItem.setId("ChangeLocationContextPopup");
        _changeLocationMenuItem.setParent(_viewListBoxContextMenu);

        _viewListBox.setId("LocationListBox");
        _viewListBox.setWidth("100%");
        _viewListBox.setHeight("450px");
        _viewListBox.setMultiple(false);
        _viewListBox.setParent(gpBox);

        Listhead lh = new Listhead();
        lh.appendChild(new Listheader("Name",null,"200px"));
        lh.appendChild(new Listheader("Location",null,"300px"));
        lh.appendChild(new Listheader("Office Number",null,"100px"));
        lh.appendChild(new Listheader("Mobile Number",null,"100px"));
        lh.appendChild(new Listheader("Pager Number",null,"100px"));
        lh.setParent(_viewListBox);

        ViewItemRenderer itemRenderer = ViewItemRenderer.getInstance();
        itemRenderer.setContextMenu(_viewListBoxContextMenu);
        _viewListBox.setItemRenderer(itemRenderer);
        _viewListBox.setModel( _contactSharedData.getProxy(this.getDesktop()));

        return;
    }

    @Override
    public void onClose() {
        super.onClose();
        return;
    }
}

public class ViewItemRenderer implements ListitemRenderer {
    private final static ViewItemRenderer _instance = new ViewItemRenderer();
    private Menupopup           _contextPopup = null;

    private ViewItemRenderer() {
    }

    public static ViewItemRenderer getInstance() {
        return _instance;
    }

    public void setContextMenu(Menupopup contextPopup) {this._contextPopup = contextPopup;}
    public Menupopup getContextMenu() {return this._contextPopup;}

    @Override
    public void render(Listitem item, Object data) {

        item.setContext(_contextPopup);
        item.setValue( (Contact)data);
        item.setVisible(true);

        //Do Other Work

       return;
    }
}