ComboBox display empty list after model change

import QtQuick 2.5
import Qt.labs.controls 1.0

ApplicationWindow {
    visible: true
    width: 640
    height: 480

    ComboBox {
        id: comboBox

        anchors.centerIn: parent
        model: [
            "111",
            "222",
            "333"
        ]
    }

    Button {
        anchors.bottom: parent.bottom
        anchors.horizontalCenter: parent.horizontalCenter
        text: "Change Model"
        onClicked: comboBox.model = [ "444", "555", "666" ]
    }
}