JavaFX how to assign content to a child node UI controller
<p>I have written the following code, where I assigned the MasterNode as a new treeView.</p>

<pre><code>MasterDetailPane pane = new MasterDetailPane();
pane.setMasterNode(new TreeView());
pane.setDetailNode(new PropertySheet());
pane.setDetailSide(Side.BOTTOM);
pane.setShowDetailNode(true);
</code></pre>

<p>Now I want to populate and manipulate that TreeView programmatically.  I think I need to do a pane.getMasterNode()..., but some how I should be able to access that controller and say something like,</p>

<pre><code>pane.getMasterNode().setRoot(rootNode);
</code></pre>

<p>But I can't figure out how to get a hold of the controller, and get it cast as the right type of object in order to assign the rootNode.   How to do I access that buried controller to assign a rootNode?</p>