title: Is it possible to reload the same FXML/Controller instance?
body: <p><strong>Goal:</strong> Implement a standard "Settings" GUI window. Categories in a <code>ListView</code> on the left and the corresponding options in a <code>Pane</code> on the right.
  <a href="https://i.stack.imgur.com/QDTRT.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QDTRT.jpg" alt="enter image description here"></a>
  (please ignore the obvious bug with repeated categories; still working on it)</p>
  
  <p>I have a main window for the overall Settings window that contains a <code>ListView</code> with all the categories of settings.  The right side of the window has an <code>AnchorPane</code> which is used to load separate FXML files for each category when one is selected from the list.</p>
  
  <p>When a user selects a category, I need them to be able to edit the settings on the right, switch to another category and make more changes. Yet, if they return to the first category, the changes made there persist.</p>
  
  <p>My obvious issue is that each time a user changes categories, the <code>FXMLLoader</code> reloads the FXML file and controller, resetting all controls within to their default values.</p>
  
  <p>So is it possible to reuse an FXML file that has already been loaded and altered? </p>
  
  <p><strong>Research:</strong> </p>
  
  <p>The only answer I found that seems to address the issue is <a href="https://stackoverflow.com/questions/20919691/how-to-swich-javafx-application-controller-without-reloading-fxml-file">How to swich javafx application controller without reloading FXML file?</a>. That mentions using a Singleton for the FXML controller, but does not address the issue with the FXML file itself being reloaded each time.</p>
  
  <p>I would be happy if someone could point to a basic example of this type of Settings menu.</p>