ListView positionViewAtBeginning() does not take topMargin into account

import QtQuick

Rectangle {
    width: 500
    height: 500
    color: "lightblue"

    ListView {
        id: listView
        anchors.fill: parent
        topMargin: 20
        model: 20

        delegate: Rectangle {
            required property int index
            width: parent.width
            height: 30
            border.width: 1

            Text { 
                anchors.verticalCenter: parent.verticalCenter
                text: "Item " + index
            }

            MouseArea {
                anchors.fill: parent
                onClicked: listView.positionViewAtBeginning()
            }
        }
    }
}