何度閉じてもダイアログが出てくるScalaスクリプト

dialog.scala

import java.awt._, event._
import javax.swing._

import scala.util.Random

val (screenCenterW, screenCenterH) = {
  val ss = Toolkit.getDefaultToolkit().getScreenSize
  (ss.getWidth.toInt / 2, ss.getHeight.toInt / 2)
}

val label = new JLabel("何回閉じても無駄ですよ～ww")

def randomLocation(): (Int, Int) =
  (screenCenterW + Random.nextInt(200) - 200, screenCenterH + Random.nextInt(200) - 200)

def newDialog(): Unit = {
  val dialog = new JDialog()
  dialog.setSize(300, 200)
  val (x, y) = randomLocation()
  dialog.setLocation(x, y)
  dialog.add(label)
  dialog.setVisible(true)
  dialog.addWindowListener(new WindowAdapter {
    override def windowClosing(e: WindowEvent): Unit = {
      newDialog()
    }
  })
}

newDialog()