Application lose activeFocus permanently by the popup window on Mac OS X

import QtQuick 2.1
import QtQuick.Window 2.0
import QtQuick.Controls 1.0

ApplicationWindow {
    Window {
        id: popup
        flags: Qt.Popup
    }
    Timer {
        interval: 500
        running: true
        repeat: true
        onTriggered: {
            console.log(activeFocusItem);
            popup.show();
            popup.hide();
        }
    }
}