Menus have wrong size after the window has been moved to a monitor with a differnt DPI

#include <QApplication>
#include <QtWidgets>

class MenuWidget : public QMainWindow
{
public:
    MenuWidget()
    {
        auto fileMenu = menuBar()->addMenu(tr("&File"));
        fileMenu->addAction("Some File Menu Entry");
        fileMenu->addAction("Some File Menu Entry");
        fileMenu->addAction("Some File Menu Entry");
        fileMenu->addAction("Some File Menu Entry");
        fileMenu->addAction("Some File Menu Entry");
    }
};
int main(int argc, char *argv[])
{
    QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QApplication a(argc, argv);
    MenuWidget w;
    w.show();
    return a.exec();
}