Menmonics do not work with checkable QtQuickControls 2 MenuItem

import QtQuick.Controls 2.2

ApplicationWindow {
    property bool flag

    width: 400; height: 400
    visible: true

    Button {
        text: "&Open menu"

        onClicked: menu.open()

        Menu {
            id: menu

            MenuItem {
                text: "&Item"
                checkable: true
                checked: flag
                onTriggered: {
                    flag = checked
                    console.log("flag=", flag)
                }
            }
        }
    }
}