public override void Update(GameTime gameTime)
        {
            if (InputHelper.InputCancelPressed())
            {
                RemoveScreen(this);
            }
            else if (InputHelper.InputConfirmPressed() && ListPresentUnit.Count > 0)
            {
                GameScreen CustomizeScreen = SelectedUnit.GetCustomizeScreen();

                if (CustomizeScreen == null)
                {
                    CustomizeScreen = new DefaultUnitUpgradesScreen(SelectedUnit, ActiveParser);
                }

                PushScreen(CustomizeScreen);
            }
            else
            {
                UnitSelectionMenu.Update(gameTime);
            }
        }
        public override void Update(GameTime gameTime)
        {
            switch (Stage)
            {
            case -1:
                UnitSelectionMenu.Update(gameTime);
                if (InputHelper.InputConfirmPressed() && ListPresentUnit.Count > 0)
                {
                    CursorIndexUnitPart = 0;
                    ListTerrainChoices.AddRange(SelectedUnit.ListTerrainChoices);
                    GoToPartChange();
                }
                break;

            case 0:
                UpdatePartSelectionPart1();
                break;

            case 1:
                UpdatePartSelectionPart2();
                break;

            case 2:
                SelectPartLinkedUnit();
                break;
            }
            if (InputHelper.InputCancelPressed())
            {
                if (Stage > -1)
                {
                    Stage--;
                }
                else
                {
                    RemoveScreen(this);
                }
            }
        }