title: An error occurred while finding the resource dictionary
body: <p>I have a merged resource dictionary in <code>App.xaml</code> Main assembly, which combines various resource dictionaries from separate assemblies: Common and PresentationLayer.</p>
  
  <pre><code>&lt;Application.Resources&gt;
      &lt;ResourceDictionary&gt;
          &lt;ResourceDictionary.MergedDictionaries&gt;
              &lt;ResourceDictionary Source="/Common;component/Themes/Button.xaml"/&gt;
              &lt;ResourceDictionary Source="/PresentationLayer;component/DataTemplates/AppointmentsDataTemplates.xaml"/&gt;
          &lt;/ResourceDictionary.MergedDictionaries&gt;
      &lt;/ResourceDictionary&gt;
  &lt;/Application.Resources&gt;
  </code></pre>
  
  <p>At run time the styles in the resource dictionaries are applied to the controls correctly. However, at design time the styles are not applied and Visual Studio 2012 keeps giving the following error:</p>
  
  <pre><code>An error occurred while finding the resource dictionary "/Common;component/Themes/Button.xaml".
  </code></pre>
  
  <p>And warning:</p>
  
  <pre><code>The resource "BannerButton" could not be resolved.
  </code></pre>
  
  <p>I came across <a href="https://stackoverflow.com/q/8475674/896265">this post</a> but the problem persists despite Build Action set to Resource. Also, I did not have this problem when running under Visual Studio 2010 or Expression Blend 4. The Main assembly definitely holds a reference to the Common assembly and I haven't changed the Pack URIs.</p>