title: How to customize disclosure cell in view-based NSOutlineView
body: <p>I'm trying to customize the disclosure arrow appearance in my view-based NSOutlineView. I saw that it's recommended to use</p>
  
  <pre><code>- (void)outlineView:(NSOutlineView *)outlineView willDisplayOutlineCell:(id)cell forTableColumn:(NSTableColumn *)tableColumn item:(id)item
  </code></pre>
  
  <p>delegate method to achieve it. The problem is that this method is not called for some reason. I have 2 custom cell views - one for item and second for header item. May be this method is not called for view-based outline views? May be something became broken in Lion?</p>
  
  <p>Please shed some light.</p>