Button menu pops up at wrong position on a QGraphicsProxyWidget

#include <QApplication>
#include <QGraphicsView>
#include <QToolButton>
#include <QMenu>

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

    QGraphicsScene scene;
    auto *button = new QToolButton();
    button->setText("B");
    auto *menu = new QMenu();
    menu->addAction("Action1");
    menu->addAction("Action2");
    button->setMenu(menu);
    button->setPopupMode(QToolButton::InstantPopup);
    scene.addWidget(button);

    QGraphicsView view(&scene);
    view.show();
    return a.exec();
}