Window with Qt.Dialog flag has no decoration on Windows

import QtQuick 2.1
import QtQuick.Window 2.0

Rectangle {
    width: 360
    height: 360
    Text {
        anchors.centerIn: parent
        text: "Show Window with Qt.Dialog flag"
    }
    MouseArea {
        anchors.fill: parent
        onClicked: {
            window.show();
        }
    }
    Window {
        id: window
        flags: Qt.Dialog
    }
}