title: (NSWindowButton) NSWindow.standardWindowButton button not highlighting
body: <p>When i use the following to create a button</p>
  
  <pre><code>NSWindow.standardWindowButton(NSWindowButton.ZoomButton, forStyleMask: 0)
  </code></pre>
  
  <p>I get a button that doesn't react to mouse hover events. I can augment this by creating a container view with a <code>NSTrackingArea</code> and manually triggering the <code>highlight</code> method but it produces a clicked state.</p>
  
  <p><a href="https://i.stack.imgur.com/sXoNQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sXoNQ.png" alt="enter image description here"></a></p>
  
  <p>Is there a way to somehow force the button into the expected behavior state without the darkened background?</p>
  
  <p>I have been trying to avoid subclassing <code>NSButton</code>, but it seems like i may have to, and I'm just in a state of denial.</p>