if (baseUrl == null) baseUrl = "error:FileNotFound";
    public void setBaseURL(String url) {        baseUrl = resolveURI(url);        //setBaseURL is called by view when document is loaded        if (index >= 0) {            String historic = (String) history.get(index);            if (historic.equals(baseUrl)) return;//moved in history        }        index++;        for (int i = index; i < history.size(); history.remove(i)) ;        history.add(index, baseUrl);    }