Accordions don't seem to change the expanded pane correctly programmatically. See the code example below


package foo;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Accordion;
import javafx.scene.control.Button;
import javafx.scene.control.TitledPane;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

public class Main1 extends Application
{

  public static void main(String[] args)
  {
    launch(args);
  }

  private Parent getContent()
  {
    VBox box = new VBox(10);

    final TitledPane pane1 = new TitledPane();
    pane1.setText("title 1\nLong text long text");
    pane1.setContent(new Rectangle(100, 40, Color.SKYBLUE));
    TitledPane pane2 = new TitledPane();
    pane2.setText("title 2\nLong text long text");
    pane2.setContent(new Rectangle(100, 40, Color.BLUEVIOLET));
    final Accordion acc = new Accordion();
    acc.getPanes().addAll(pane1, pane2);
    acc.setExpandedPane(pane2);

    Button b = new Button("Change to Pane 1");
    b.setOnAction(new EventHandler<ActionEvent>()
    {

      @Override
      public void handle(ActionEvent arg0)
      {
        System.err.println("Changing Pane");
        acc.setExpandedPane(pane1);
      }

    });


    box.getChildren().addAll(acc, b);

    return box;
  }

  public void start(Stage stage)
  {
    stage.setX(100);
    stage.setY(100);
    stage.setWidth(300);
    stage.setHeight(300);
    Scene scene = new Scene(getContent());
    stage.setScene(scene);
    stage.show();
  }

}