title: Attributes Inspector Not Displaying Navigation Item Attributes
body: <p>I want to customize the title of the back bar button on a navigation controller using the attributes inspector in storyboards.  The following image illustrates what I expect to see in the attributes inspector when the navigation item is selected (taken from another post):</p>
  
  <p><img src="https://i.stack.imgur.com/Gv4Wu.png" alt="enter image description here"></p>
  
  <hr>
  
  <p>When I select my navigation controller my attributes inspector is empty:</p>
  
  <p><img src="https://i.stack.imgur.com/6RuN3.png" alt="enter image description here"></p>
  
  <hr>
  
  <p>I'm using Xcode 6 but also went back to 5.1 and had the same issue.  I opened another project and had no problem so I'm guessing that something I set (or the way I implemented the navigation bar) is disabling the attributes inspector for my navigation bar.</p>
  
  <p>Any ideas on what is causing this?</p>