title: JavaFX hover property
body: <p>I have a GridPane which is populated by rectangles. What I want to do is to display a new pane while hovering over a particular rectangle(member of the grid pane). Lets have an example with this VBox code example below. How could I make it display on hover ?</p>
  
  <pre><code>    Rectangle r = new Rectangle(RECTANGLE_SIZE, RECTANGLE_SIZE);
              r.hoverProperty().addListener((observable) -&gt; {
                  r.setFill(Color.BLACK);
                  VBox box = new VBox();
                  Button x = new Button("Test");
                  box.getChildren().add(x);
              });
  </code></pre>
  
  <p>the set fill works properly</p>