title: JavaFX. How to make the border of imageview, when I click the imageview?
body: <p>In javaFX, I want make a imageview that can change border when I click.
  When click once, then imageview has a border.
  When click again, then imageview doesn't have a border.</p>
  
  <p>How can I make that?
  Thanks in advance!</p>