title: IB_DESIGNABLE build failed when using class from within a framework
body: <p>I created a new embedded framework. Within the framework I created a class called "WBButton", which is a subclass of UIButton.  I have set the IB_DESIGNABLE and added IBInspectable attributes to allow configuration through Interface builder, as explained <a href="https://developer.apple.com/library/ios/recipes/xcode_help-IB_objects_media/chapters/CreatingaLiveViewofaCustomObject.html">here</a>.</p>
  
  <p>It works fine when I test it from within my framework (by adding a sample .xib and placing the button on the screen), but when adding the custom button to a nib located on the project which contains the framework, I get a "Build Failed" message next to the "Designables" (see below).</p>
  
  <p>Also, what does "Module" mean in Interface builder?</p>
  
  <p><img src="https://i.stack.imgur.com/KDggH.png" alt="enter image description here"></p>