private void PushMenu(Menu menu, object[] parameters)
        {
            if (menu.IsAlwaysVisible())
            {
                throw new ArgumentException("Unable to start Menu : menu is allways visible.");
            }
            if (!HasActivityRunning())
            {
                throw new ArgumentException("Unable to start Menu : no activity running.");
            }
            StackedActivity currentActivity = GetCurrentActivity();
            StackedMenu     stackedMenu     = currentActivity.GetMenu(menu);

            if (stackedMenu == null)
            {
                throw new ArgumentException("Unable to start Menu : menu is not part of the current activity.");
            }
            stackedMenu.SetParameters(parameters);
            menuStack.Push(stackedMenu);
        }
        private void HideCurrentActivity()
        {
            StackedActivity currentActivity = GetCurrentActivity();

            currentActivity.OnStop();
        }