code: public void setLayerColor(String color, int layer) {
  
          switch (layer) {
              case COLORBAR_A:
                  m_colorA.getElement().getStyle().setBackgroundColor(color);
                  break;
              case COLORBAR_B:
                  m_colorB.getElement().getStyle().setBackgroundColor(color);
                  break;
              case COLORBAR_C:
                  m_colorC.getElement().getStyle().setBackgroundColor(color);
                  break;
              case COLORBAR_D:
                  m_colorD.getElement().getStyle().setBackgroundColor(color);
                  break;
              default:
                  return;
          }
      }
docs: Sets the color of a particular layer.<p>
  @param color Hexadecimal notation of RGB to change the layer's color
  @param layer Which layer to affect