private void btnAltMasa1_Click(object sender, EventArgs e)

        {

            foreach (SimpleButton item in buttons)

            {

                item.Appearance.BackColor = Color.Transparent; // Color.Empty varsayılan rengi

                item.Appearance.Options.UseBackColor = true;

            }

            (sender as SimpleButton).Appearance.BackColor = Color.Lime;

        }