Execute the test below - when the scrollpane is removed it's still referenced so it can't get GC'd.

public class ScrollPaneMemoryLeakTest extends Application
{
  private MyScrollPane myPane;
  
  public static void main(String[] args)
  {
    Application.launch(args);
  }

  @Override
  public void start(Stage stage)
  {
    final FlowPane root = new FlowPane(10, 10);
    
    myPane = new MyScrollPane();
    root.getChildren().add(myPane);
    
    Button b = new Button("Remove Pane");
    b.setOnAction(new EventHandler<ActionEvent>()
    {
      @Override
      public void handle(ActionEvent event)
      {
        root.getChildren().remove(myPane);
        myPane = null;
      }
    });
    root.getChildren().add(b);
    
    Scene scene = new Scene(root, 800, 600);
    stage.setScene(scene);
    stage.show();
  }

  private static class MyScrollPane extends ScrollPane
  {
  }
}