title: Windows phone wrapPanel does not exist error
body: <p>I have a xaml which has the following code.</p>
  
  <pre><code>&lt;ListBox.ItemsPanel&gt;
      &lt;ItemsPanelTemplate&gt;
          &lt;toolkit:WrapPanel Orientation="Horizontal"/&gt;
      &lt;/ItemsPanelTemplate&gt;
  &lt;/ListBox.ItemsPanel&gt;
  </code></pre>
  
  <p>Now the error says that 
  The name wrappanel does exist in the namespace clr-namespace:Microsoft.Phone.Controls etc...</p>
  
  <p>Any idea how to fix it.</p>