Selection fix

selection.js

//Note:  some may have selectedWidget, some may not , ignore it if it is not yours.
// while selecting a module, set topic and selectedWidget to null so that you don't retain the existing selection
// while selecting a lesson, set widget and selectedWidget to null

// This is just a sample code
  this.state={
// ...
selectedModule: course.modules[0],
selectedLesson: course.modules[0].lessons[0],
selectedTopic: course.modules[0].lessons[0].topics[0]
// ...
}

// To handle  the issue, 
// replace that code and initialize with 
{
selectedModule: null
selectedLesson: null
selectedTopic:  null


}


render(){
  
  return <div>
    {this.state.selectedModule && <LessonList>}
    {this.state.selectedLesson && <TopicList>}
    {this.state.selectedTopic && <WidgetList>}
    
    <div>
}