title: DecimalUpDown (Extended WPF toolkit) - Source only gets updated on lost focus
body: <p>I am using Extended WPF toolkit's DecimalUpDown control with its Value property binded to a Decimal? as follows:</p>
  
  <pre><code>   &lt;extToolkit:DecimalUpDown Value="{Binding BlahBlah, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" ShowButtonSpinner="False" /&gt;
  
  private Decimal? blahblah = 5;
      public Decimal? BlahBlah
      {
          get { return blahblah; }
          set { blahblah = value; }
      }
  </code></pre>
  
  <p>I noticed that as I key in the number in the textbox, the Value does not get updated until I click outside the control. Its ValueChanged event is not fired as well until I click outside. </p>
  
  <p>I intend for the value to be updated as soon as the user changes the Value (i.e. real-time). Is there anyway to accomplish this?</p>