code: public void setColor(TimeArea area, Color color) {
          // If null was supplied, then use the default color.
          if (color == null) {
              color = area.defaultColor;
          }
          // Save the color to the color map.
          colors.put(area, color);
  
          // Call any "updating functions" that are appropriate for the specified area.
          if (parent != null) {
              parent.zDrawTextFieldIndicators();
          }
      }
docs: setColor, This sets a color for the specified area. Setting an area to null will restore the
  default color for that area.