Tweak hover detail CSS
Ensure graph-toggling-via-legend works properly

* Earlier, to update the legend items, the render() method was used.
  The side-effect of this is, that method clears all the graph toggling
  functionality that is set up while rendering for the first time. One
  way to achieve this is to call the render() and initializing the
  toggle and highlight classes everytime. The other way to do this,
  apparently, is to add circular references and lose the render() method
  call entirely.