public String AddPage(String pageName)
        {
            /* adds a page with name "Page#" if no name is specified */
            return (name == null) ? NamePage("Page" + (pages.Count + 1)) : NamePage(pageName);
        }

        public String NamePage(String name)
        {
            this.pages.Add(new Page(this, name));
            this.undoStack.Add(new UndoDataStructure(null, "Add"));
            return name;
        }