#include <QtWidgets>

int main(int argc, char *argv[])
{
    // QApplication::setAttribute(Qt::AA_DontUseNativeMenuBar);
    // QApplication::setAttribute(Qt::AA_DontUseNativeMenuWindows);
    QApplication app(argc, argv);
    QMainWindow mainWindow;
    mainWindow.resize(400, 400);
    mainWindow.show();

    auto *centralWidget = new QWidget;
    mainWindow.setCentralWidget(centralWidget);
    auto *label = new QLabel(centralWidget);
    label->setPixmap(QIcon::fromTheme("edit-redo").pixmap(32, 32));

    // reproducer for QMdiSubWindow menu entries
    QMdiArea area;
    auto sw = new QMdiSubWindow;
    sw->setWindowTitle("SubWindow");
    area.addSubWindow(sw);
    area.show();

    return app.exec();
}

import QtQuick
import QtQuick.Controls.Windows

ApplicationWindow {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    Button {
        icon.name: "edit-redo"
        icon.width: 100
        icon.height: 100
    }
}