title: smartGWT date input validator
body: <p>I'm using <code>DateTimeItem</code> for my start and end dates. I don't want the user to be able to select invalid dates, like <code>13/44/2014</code>:</p>
  
  <p>First image is a example of valid date, the second (one below) is a invalid date.</p>
  
  <p><img src="https://i.stack.imgur.com/DFkbj.png" alt="enter image description here"></p>
  
  <p>How do I avoid the second one from happening?</p>