Translation doesn't apply for Mac OS X system menu

#include <QApplication>
#include <QDialog>
#include <QTranslator>
#include <QLocale>
#include <QMessageBox>
#include <QLibraryInfo>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QTranslator qtTranslator;
    qtTranslator.load("qt_" + QLocale::system().name(), QLibraryInfo::location(QLibraryInfo::TranslationsPath));
    a.installTranslator(&qtTranslator);
    QWidget w;
    w.setWindowFlags(Qt::Window | Qt::Dialog);
    w.show();
    
    QMessageBox::information(0, "test", QLocale::system().name(), QMessageBox::Yes | QMessageBox::No);

    return a.exec();
}