anchor.diff:        stop.color = color;
         stop.whiteness = bright;
         stop.darkness = dark;
  +      stop.gradientlocation = externalStop.gradientlocation;
         _colorChangeCallback(stop);
       }
     }
  
positive.code:   // Called by either an external control (aka gradient_colorstops_control)
    void externalColorChange(ColorData stop) {
      _transmit = false;
      
      // An external control is telling us to switch to a new color configuration.
      color = stop.color;
  
negative.code:   ColorValue colorBoxValue = new ColorValue();
    ColorValue colorValue = new ColorValue();
    
    ColorData externalStop;
    
    bool _down = false;
    BaseSlider target;
    
  