code: protected void hoverObjectChanged (Object oldHover, Object newHover)
      {
          // deal with objects that care about being hovered over
          if (oldHover instanceof SceneObject) {
              SceneObject oldhov = (SceneObject)oldHover;
              if (oldhov.setHovered(false)) {
                  _remgr.invalidateRegion(oldhov.bounds);
              }
          }
          if (newHover instanceof SceneObject) {
              SceneObject newhov = (SceneObject)newHover;
              if (newhov.setHovered(true)) {
                  _remgr.invalidateRegion(newhov.bounds);
              }
          }
  
          // dirty the indicators associated with the hover objects
          dirtyIndicator(_indicators.get(oldHover));
          dirtyIndicator(_indicators.get(newHover));
      }
docs: A place for subclasses to react to the hover object changing.
  One of the supplied arguments may be null.