//Select the symbol background colours for current level
        private void SetBackgroundColours()
        {
            List <Colour> tmpList = colorPicker.GetColourList();

            if (backgroundColours.Count > 0)
            {
                backgroundColours.Clear();
            }

            for (int i = 0; i < 4; i++)
            {
                backgroundColours.Add(tmpList[i]);
            }
        }