title: How can I select a number or text in the spinner textfield on entry?
body: <p>I am using a javafx spinner for Integers. Is there a way to select the value in the Spinner, when I click on it or move to it with TAB? 
  Like it works for TextAreas with the following code:</p>
  
  <pre><code>myTextArea.focusedProperty().addListener((obs, isFocused, isNowFocused) -&gt; {
          if (isNowFocused) {
              myTextArea.selectAll();
     }
  })
  </code></pre>
  
  <p>selectAll() does not work for the spinner. I would like to start typing in the spinner field without previously deleting the initial value.</p>