title: Control from WPFToolkit doesn't exist in namespace
body: <p>I added to references WPFToolkit.dll and I added do my .xaml file following line:</p>
  
  <pre><code>xmlns:toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WpfToolkit"
  </code></pre>
  
  <p>and before following line:</p>
  
  <pre><code>xmlns:toolkit="http://schemas.microsoft.com/wpf/2008/toolkit"
  </code></pre>
  
  <p>In both cases in line</p>
  
  <pre><code>&lt;toolkit:NumericUpDown Value="10" Increment="1" Maximum="10" Minimum="0" /&gt;
  </code></pre>
  
  <p>I have error:</p>
  
  <blockquote>
    <p>Error 1   The tag 'NumericUpDown' does not exist in XML namespace 'http://schemas.microsoft.com/wpf/2008/toolkit'. Line 20 Position 18.   C:\Users\Diament\Documents\Visual Studio 2008\Projects\MyBasicFlyffKeystroke\MyBasicFlyffKeystroke\Window.xaml  20  18  MyBasicFlyffKeystroke</p>
  </blockquote>
  
  <p>Where is the problem? :(</p>