public void Clicked()
    {
        TowerInstance selectedTower = Game.GetSelectedTower();

        if (selectedTower != null)
        {
            if (Game.GetLumber() >= upgrade.GetCost())
            {
                selectedTower.AddUpgrade(upgrade);

                upms.Refresh();

                Game.AddLumber(-upgrade.GetCost());
            }
        }
    }