title: Visual Studio 2015 still didn't fix the error when setting IsChecked to {x:Null}?
body: <p>A simple project with only a window and a check box like this:</p>
  
  <pre><code>&lt;CheckBox IsChecked="{x:Null}"/&gt;
  </code></pre>
  
  <p>Will throw this error:</p>
  
  <pre><code>Invalid value for property 'IsChecked':  
  'Microsoft.VisualStudio.DesignTools.Xaml.LanguageService.Semantics.XmlValue'
  </code></pre>
  
  <p>This problem was said to be fixed 4 months ago <a href="https://connect.microsoft.com/VisualStudio/feedback/details/1112682/wpf-checkbox-ischecked-cannot-be-set-to-indeterminate" rel="nofollow noreferrer">here</a></p>
  
  <p>But still presets in the enterprise final version! 
  proof : 
  <a href="https://i.stack.imgur.com/9pDX8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9pDX8.png" alt="enter image description here"></a>
  <a href="https://i.stack.imgur.com/SGh7F.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SGh7F.png" alt="enter image description here"></a></p>
  
  <p>Is there any fix / workaround for this annoying problem?<br>
  Edit : I added a new ticket to microsoft about this <a href="https://connect.microsoft.com/VisualStudio/feedback/details/1611888/xaml-editor-error-invalid-value-for-property-in-handler-and-ischecked-bug-remains-in-the-enterprise-version-of-vs-2015" rel="nofollow noreferrer">here</a></p>