ChartView disappears when reparented to another windows contentItem

import QtQuick 2.7
import QtQuick.Window 2.2
import QtQuick.Controls 2.0
import QtCharts 2.0
import QtQuick.Layouts 1.3
//

Window {
    id: mainWindow
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello ChartTest")

    // Private Properties
    property Window __subWindow: null;

    // Private Methods
    function __createSubWindow() {
        mainWindow.__subWindow = subWindowComponent.createObject();
        console.assert(mainWindow.__subWindow !== null);
    }

    Component {
        id: subWindowComponent
        Window {
            visible: true
            x: 10
            y: 10
            height: 200
            width: 200
        }
    }

    RowLayout {
        Button {
            id: popButton
            text: "Create SubWindow"
            onClicked: mainWindow.__createSubWindow();
        }

        Button {
            id: reparentButton
            text: "Reparent Chart"
            onClicked: pieChart.parent = __subWindow.contentItem;
        }

        Button {
            id: changeValue
            text: "Change Value"
            onClicked: {
                var slice = pieSeries.find("eaten");
                console.assert(slice !== null);
                if (slice !== null) {
                    slice.value = 20;
                }
            }
        }
    }

    ChartView {
        id: pieChart
        width: 100
        height: 100
        theme: ChartView.ChartThemeBrownSand
        antialiasing: true
        legend.visible: false
        margins.top: 0
        margins.left: 0
        margins.bottom: 0
        margins.right: 0
        anchors.centerIn: parent

        PieSeries {
            id: pieSeries
            size: 1
            onClicked: {
                pieSeries.find("notEaten").exploded = true;
            }

            PieSlice { label: "eaten"; value: 94.9 }
            PieSlice { label: "notEaten"; value: 5.1 }
        }
    }
}