title: Scene loads too slow
body: <p><br>
  I am building a JavaFX application and I am wondering if there is a recommendation (best practice) on how to load new <code>Scene</code> in current <code>Stage</code> as fast as possible.<br><br>
  Currently what I am doing is (more or less) this:<br></p>
  
  <pre><code>Parent root = (Parent)myFXLoader.load();
  currentStage.setScene(new Scene (root);
  </code></pre>
  
  <p>The above works fine and fast enough for simple <code>Scene</code>s BUT when loading more complicated scenes that initialize <code>TableView</code>s, <code>Combobox</code>es etc the transition between <code>Scene</code>s takes many seconds which is annoying.<br><br>
  All the initialization I do in inside the <code>Controller</code>'s <code>initialize(URL url, ResourceBundle rb)</code> method.<br>
  There I add the items to the <code>Choice/Combo</code> boxes, initialize <code>TableView</code> etc but as I said, it takes too much time.
  <br>
  Am i doing something wrong? Should I initialize somewhere else? <br><br>
  Thank you.
  <br><br>
  <strong>EDIT:</strong><br>
  Anyone interested in helping with this, or even get ideas for their project, I have uploaded a part of my project (Netbeans project) at google.com.<br>
  You can check it out using SVN. This is the link:<br>
  <a href="http://tabularasafx.googlecode.com/svn/trunk/" rel="nofollow noreferrer">http://tabularasafx.googlecode.com/svn/trunk/</a><br>
  userName: tabularasafx-read-only<br>
  no password required<br>
  <em>Instructions after you run the project:</em><br>
  First screen is login screen, just click OK<br>
  Second screen is "homePage", there you can see a treeView menu and navigate to 4 different screens<br>
  My issue is the loading time of classes->create page. Take a look at it and let me know if you find anything<br><br>
  <strong>EDIT:</strong><br>
  I made 3 changes that @jewelsea suggested.<br>
  1. I used a HashMap to keep all the controllers for each screen<br>
  2. I update only part of the Scene and not the whole Scene<br>
  3. I used the answer of <a href="https://stackoverflow.com/questions/11734885">JavaFX2 - very poor performance when adding custom made (fxml)panels to gridpane dynamically</a> to help the controllers load faster as described in the answer.<br><br>
  Everything is much much faster now!!!!<br>
  Feel free to use the project as a guideline<br>
  Also I update the program to navigate through 3 screens for better understanding<br>
  note that my code is a messy</p>