title: WebView - Failed to set (contentViewController) user defined inspected property on (NSWindow)
body: <p>I create a new Xcode project from scratch and it compiles fine. </p>
  
  <p>I add a label to the View Controller and this compiles / runs / shows fine.</p>
  
  <p>I then drag in a WebView into the View Controller but get this message when I run the application:</p>
  
  <pre><code>Failed to set (contentViewController) user defined inspected property on (NSWindow): *** -[NSKeyedUnarchiver decodeObjectForKey:]: cannot decode object of class (WebView)
  </code></pre>
  
  <p>What am I doing wrong?</p>