private void Save(string filename)
        {
            File.WriteAllText(filename, DocumentText, Encoding.UTF8);
            UnsavedChanges = false;

            if (LastSavedDocuments.Contains(filename) == true)
            {
                LastSavedDocuments.Remove(filename);
            }
            LastSavedDocuments.Add(filename);

            UpdatePageTitle(filename);
        }
        private void LoadLastDocuments()
        {
            var lastDocuments = string.IsNullOrEmpty(Properties.Settings.Default.LastSavedDocuments) == false?Properties.Settings.Default.LastSavedDocuments.Split(";").ToList() : new List <string>();

            lastDocuments.ForEach(x => LastSavedDocuments.Add(x));
        }