code: private void initializeScene() {
  
          final Stage currentStage = this.stage;
  
          final KeyCode fullKeyCode = fullScreenKeyCode();
          final KeyCode iconKeyCode = iconifiedKeyCode();
  
          // Attach the handler only if necessary, these 2 method can be overridden to return null
          if (fullKeyCode != null && iconKeyCode != null) {
  
              this.scene.addEventFilter(KeyEvent.KEY_PRESSED, keyEvent -> {
  
                  // Manage F11 button to switch full screen
                  if (fullKeyCode != null && fullKeyCode == keyEvent.getCode()) {
                      currentStage.setFullScreen(!currentStage.isFullScreen());
                      keyEvent.consume();
                      // Manage F10 button to iconify
                  } else if (iconKeyCode != null && iconKeyCode == keyEvent.getCode()) {
                      currentStage.setIconified(!currentStage.isIconified());
                      keyEvent.consume();
                  }
  
              });
          }
  
          // The call customize method to allow extension by sub class
          customizeScene(this.scene);
  
          // Add the default Style Sheet if none have been added
          manageDefaultStyleSheet(this.scene);
  
      }
docs: Initialize the default scene.