title: Keydown Event fires twice
body: <p>On a Windows store App, I have this simple TextBox</p>
  
  <pre><code>&lt;TextBox Name="TextBoxUser" HorizontalAlignment="Right" Width="147" Margin="20,0,0,0" KeyDown="TextBox_KeyDown" /
  </code></pre>
  
  <p>That has a KeyDown Event associated with it.</p>
  
  <pre><code>        private async void TextBox_KeyDown(object sender, KeyRoutedEventArgs e)
      {
          if (e.Key == Windows.System.VirtualKey.Enter)
          {
             Debug.WriteLine("LA");
          }
      }
  </code></pre>
  
  <p>And the output of this function is:</p>
  
  <blockquote>
    <p><br>LA<br>LA</p>
  </blockquote>
  
  <p>although I press Enter only once, it prints 2 times.
  Any reason for that or am I doing something wrong?</p>