title: JavaFX - ComboBox listener for its textfield
body: <p>I'm not even sure how to correctly ask this question, but is it possible to add listener here (on this textfield within <code>ComboBox</code>), when <code>ComboBox</code> is set as editable:</p>
  
  <p><img src="https://i.stack.imgur.com/nPheJ.jpg" alt="enter image description here"></p>
  
  <p>Currently I'm using 2 kinds of listeners for <code>ComboBox</code>. Mouse and Change listener. <code>MouseListener</code> for clicks on <code>ComboBox</code> and <code>ChangeListener</code> for selection of items within <code>ComboBox</code>. But I have no idea what kind of listener should I use to listen for text entry.</p>