title: Scala swing GUI - Compiler indicates that some cases in my reactions block are unreachable?
body: <p>This is an excerpt from a larger body of code with non pertinent code removed for brevity.  I've tested the code below on it's own (as a single class in a new project) and verified that the same exact issue persists.  So I know that the problem is specific to the code contained here.</p>
  
  <pre><code>object HumanGUI extends SimpleGUIApplication with Logs {
  
    PropertyConfigurator.configure("log4j.properties")
  
    def top = new MainFrame {
      title = "BJ GUI"
  
    val PlayPanel = new BoxPanel(Orientation.Vertical) {
      val hitButton = new Button("Hit")
      val stayButton = new Button("Stay")
      val doubleButton = new Button("Double")
      val quitButton = new Button("Quit")
  
      contents += hitButton
      contents += stayButton
      contents += doubleButton
      contents += quitButton
  
      listenTo(hitButton, stayButton, doubleButton, quitButton)
      reactions += {
        case ButtonClicked(hitButton) =&gt;
          debug("Clicked Hit!")
        case ButtonClicked(stayButton) =&gt;
          debug("Clicked Stay!")
        case ButtonClicked(doubleButton) =&gt;
          debug("Clicked Double!")
        case ButtonClicked(quitButton) =&gt;
          debug("Clicked Quit!")
      }
  
      contents = new BoxPanel(Orientation.Vertical) {
        contents += playPanel
      }
    }  
  </code></pre>
  
  <p>Specifically, the compiler is telling me that the last 3 cases in this block are unreachable:  </p>
  
  <pre><code>    listenTo(hitButton, stayButton, doubleButton, quitButton)
      reactions += {
        case ButtonClicked(hitButton) =&gt;
          debug("Clicked Hit!")
        case ButtonClicked(stayButton) =&gt;
          debug("Clicked Stay!")
        case ButtonClicked(doubleButton) =&gt;
          debug("Clicked Double!")
        case ButtonClicked(quitButton) =&gt;
          debug("Clicked Quit!")
      }
  </code></pre>
  
  <p>Why would this be the case?</p>