Wrong order after changing model of Repeater inside Menu

import QtQuick 2.7
import QtQuick.Controls 2.0
import QtQuick.Layouts 1.3

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

    header: ToolBar {
        id: toolBar

        Row {
            id: buttons
            ToolButton {
                id: menuButton
                onClicked: menu.open()
                text: "open"
            }

            ToolButton {
                id: showButton
                checkable: true
                text: checked ? "hide" : "show"
            }
        }
    }

    Menu {
        id: menu

        MenuItem {
            text: "Begin"
        }

        Repeater {
            id: repeater
            model: showButton.checked ? 4 : 2
            delegate: MenuItem {
                text: index
            }
        }

        MenuItem {
            text: "End"
        }
    }
}