void OnDestroy()
 {
     if (instance == this)
     {
         instance = null;
     }
 }
    //Stack<GameObject> activeCanvasStack = new Stack<GameObject>();

    /*
     * public void InsertStack(GameObject ob)
     * {
     *      if ( ob.GetComponent<GUI_Dialog>() )
     *      {
     *              ob.gameObject.SetActive(true);
     *              activeCanvasStack.Push(ob);
     *      }
     * }
     */
    void Awake()
    {
        instance = this;

        //scrollbarABDownload.gameObject.SetActive(false);
        //Debug.LogError (PlayerPrefs.GetString (PlayerPrefHandler.keyUserName));
    }