private void dispatcherTimer_Tick(object sender, EventArgs e)
        {
            this.TickCount++;

            if (this.TickCount == 5)
            {
                if (this._Users.Count == 0)
                {
                    NewUserWindow nuw = new NewUserWindow(this._Users);
                    nuw.Show();
                    this.Close();
                }
                else
                {
                    StartupWindow sw = new StartupWindow(this._Users);
                    sw.Show();
                    this.Close();
                }
            }
        }
        //OK
        private void menu_file_logout_Click(object sender, RoutedEventArgs e)
        {
            string path = "Stockholder.json";
            List<User> ListOfUsers = new List<User>();

            if (File.Exists(path))
            {
                string input = this.ReadFromFile(path);

                if (!string.IsNullOrEmpty(input) && !string.IsNullOrWhiteSpace(input))
                {
                    ListOfUsers = this.JSS.Deserialize<List<User>>(input);
                }
            }
            else
            {
                File.Create(path);
                this.SaveException(string.Format("Chybějící soubor {0}.", path));
            }

            StartupWindow sw = new StartupWindow(ListOfUsers);
            sw.Show();
            this.Close();
        }