title: NSButton action in NSOutlineView not being called?
body: <p>OK, so I have an <code>NSOutlineView</code> (populated via <code>NSTreeController</code>).</p>
  
  <p>Now this Outline View is View-based.</p>
  
  <p>I've added 2 buttons inside the Table View Cell and assigned them 2 actions (as one would normally do).</p>
  
  <p>However, none of them is being called when I click the buttons.</p>
  
  <p>What is going on? Or - better phrased - what <em>could</em> be going on?</p>
  
  <hr>
  
  <p><em>(This one definitely came as a surprise - since I must have done similar things more than 1 million times...)</em></p>