title: How do I implement a 3 pane NSSplitView with minimum & maximum sizes?
body: <p>I want to implement a 3-pane vertical <code>NSSplitView</code> (very similar to Mail.app). I'm not really sure where to start. I'm pretty sure I need to implement a <code>NSSplitViewDelegate</code>, but I'm not sure which methods and / or their implementations.</p>
  
  <p>The layout I want is the following:</p>
  
  <pre><code>+----------+------------------+------------------------------------+
  |          |                  |                                    |
  |          |                  |                                    |
  |          |                  |                                    |
  |          |                  |                                    |
  |  Pane 1  |      Pane 2      |               Pane 3               |
  |          |                  |                                    |
  |          |                  |                                    |
  |          |                  |                                    |
  |          |                  |                                    |
  |          |                  |                                    |
  +----------+------------------+------------------------------------+
  </code></pre>
  
  <p>I want to implement the following constraints for each of the panes:</p>
  
  <ul>
  <li>Pane 1: Minimum 140pt. Maximum: 400pt.</li>
  <li>Pane 2: Minimum 250pt. </li>
  <li>Pane 3: Minimum 400pt.</li>
  </ul>
  
  <p>Any pointers would be much appreciated.</p>