title: How to gray out an NSMenuItem?
body: <p>I'm writing an app with Swift targeted to macOS Sierra.</p>
  
  <p>I have an NSMenuItem that I'd like to gray out (so the user can't even select it).</p>
  
  <p>I have set its parent menu AutoEnableItems to FALSE in the Storyboard and verified that it's still false via logging in my code.</p>
  
  <p>When I set the isEnabled property of my NSMenuItem to false, what it does is that my action associated with the menu item isn't called (which is good) when I select that menu item, but the menu remains selectable.</p>
  
  <p>What I'd like is for it to be grayed out, and obviously not selectable by the user.</p>