Qt Controls 2.0: ComboBox doesn't load properly with async set to true

import QtQuick 2.6
import QtQuick.Window 2.0

import Qt.labs.controls 1.0

ApplicationWindow {
    visible: true
    width: 320
    height: 240
    title: qsTr("Test async")

    Loader {
        asynchronous: true
        anchors.centerIn: parent

        sourceComponent: ComboBox {
            model: ["First", "Second", "Third"]
            anchors.centerIn: parent
        }
    }
}