...
    ScrollView {
        id: sourceScrollView
        anchors.fill: parent
        anchors.margins: 10
        TextArea {
            id: sourceTextArea
            text: "1\n2\n3\n1\n2\n3\n1\n2\n3\n1\n2\n3\n1\n2\n3\n1\n2\n3\n"
            background: Rectangle {
                // Note: id required due to QTBUG-67446
                //id: sourceScrollViewBackground
                width: parent.width
                border.color: "#202020"
                color: "#a0a0a0"
            }
        }
    }
...