[QQC2] orientation change breaks the position and size of the Popup

import QtQuick 2.5
import QtQuick.Window 2.2
import QtQuick.Controls 2.1

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Rotation")
    id: root

    property bool rotateDialog: false
    property bool rotateMain: false

    Rectangle {
        color: "pink"
        rotation: rotateMain ? 90 : 0
        anchors.centerIn: parent
        width: rotateMain ? parent.height : parent.width
        height: rotateMain ? parent.width : parent.height

        Popup {
            id: popup

            x: 80
            y: 60
            width: 320
            height: 240
            background: Rectangle{
                color: "blue"
                rotation: rotateDialog ? 90 : 0
            }
            contentItem: Item {

            }
            closePolicy: Popup.NoAutoClose
        }

        Button {
            id: popupButton
            anchors.left: parent.left
            anchors.bottom: parent.bottom
            text: popup.visible ? "Close Popup" : "Open Popup"
            onClicked: popup.visible ? popup.close() : popup.open()
        }

        Button {
            id: rotateButton
            anchors.left: popupButton.right
            anchors.bottom: parent.bottom
            text: "Rotate Popup"
            onClicked: rotateDialog = !rotateDialog
        }

        Button {
            id: rotateMainButton
            anchors.left: rotateButton.right
            anchors.bottom: parent.bottom
            text: "Rotate Main"
            onClicked: rotateMain = !rotateMain
        }
    }
}