title: How to set NSConstraintBasedLayoutVisualizeMutuallyExclusiveConstraints?
body: <p>I am getting the following message from Cocoa Auto Layout mechanism:</p>
  
  <blockquote>
    <p>Set the NSUserDefault NSConstraintBasedLayoutVisualizeMutuallyExclusiveConstraints to YES to have -[NSWindow visualizeConstraints:] automatically called when this happens.</p>
  </blockquote>
  
  <p>But I don't know how to "Set the NSUserDefault NSConstraintBasedLayoutVisualizeMutuallyExclusiveConstraints to YES".</p>
  
  <p>How do I set this?</p>