code: public void highlight(Object control)
      {
          // Manage highlighting of controls.
          if (this.currentControl == control)
              return; // same thing selected
  
          // Turn off highlight if on.
          if (this.currentControl != null)
          {
              this.currentControl.getAttributes().setImageOpacity(-1); // use default opacity
              this.currentControl = null;
          }
  
          // Turn on highlight if object selected.
          if (control != null && control instanceof ScreenAnnotation)
          {
              this.currentControl = (ScreenAnnotation) control;
              this.currentControl.getAttributes().setImageOpacity(1);
          }
      }
docs: Specifies the control to highlight. Any currently highlighted control is un-highlighted.
  
  @param control the control to highlight.