Mac - Native menu bar, clicking on a submenu should not trigger QMenu::triggered(QAction*) signal

#include <QtGui>

class Window : public QMainWindow
{
    Q_OBJECT
public:
    Window()
    {
        menuBar()->setNativeMenuBar(true);
        QMenu* menu = new QMenu("Menu");
        QMenu* subMenu = new QMenu("SubMenu");
        menu->addMenu(subMenu);//->setProperty("toignore", true);
        menu->addAction("Item2");
        connect(menu, SIGNAL(triggered(QAction*)), this, SLOT(onMenuBarTriggered(QAction*)));
        menuBar()->addMenu(menu);
    }

public slots:
    void onMenuBarTriggered(QAction* action)
    {
        //if (!action->property("toignore").toBool())
            QMessageBox::information(this, "Menu triggered", action->text());
    }
};

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    Window* w = new Window;
    w->show();
    return app.exec();
}

#include "main.moc"