def live = {
    import scala.concurrent.{Future, Promise, ExecutionContext}
    import scala.swing.event._

    implicit val executionContext = ExecutionContext fromExecutorService Executors.newCachedThreadPool()

    def stepCommand: Future[Unit] = {
      val promise = Promise[Unit]()
      new Reactor {
        stepButton.enabled = true
        listenTo(stepButton)
        reactions += {case _: ButtonClicked => promise.success(()); deafTo(stepButton)}
      }
      promise.future
    }

    def autoStepCommand: Future[Unit] = {
      lazy val never = Promise[Unit]().future
      if (autoCheckBox.selected) Future {waitForStepTimeout} else never
    }

    def again: Unit = Future {awaitMessageBeingHandled(true)}.flatMap {_ =>
      if (shouldStep) {
        Swing.onEDTWait(updateDisplay)
        Future firstCompletedOf Seq(stepCommand, autoStepCommand)
      } else Future.successful(())
    }.onSuccess {case _ =>
      messageBeingHandled(false)
      again
    }

    new Reactor {
      exitButton.enabled = true
      listenTo(exitButton)
      reactions += {case _: ButtonClicked => System.exit(1)}
    }

    again
  }