title: How can I be notified when a NSComboBox selection changes IF the combo box is dynamically added with a new table row?
body: <p>I have a NSTableView and each row has a NSComboBox. 
  <img src="https://i.stack.imgur.com/36kZq.png" alt="enter image description here"></p>
  
  <p>The table column is bounded to NSArrayControllerA and each NSComboBox is bounded to NSArrayControllerB.</p>
  
  <p>I would like to be notified when the selected value in any NSComboBox changes.</p>
  
  <p>So far, I've tried to add a listener to the NSArray managed by the NSArrayControllerB, but I'm not notified about any change.</p>
  
  <p>I've also tried to add an observer to the NSTableView, with a NSComboBoxSelectionDidChangeNotification but it seems the notifications are not propagated to the parent views. And the combo boxes are dynamically created when a new row is inserted.</p>
  
  <p>thanks</p>
  
  <p><strong>UPDATE</strong>: How is the NSComboBox bound ?</p>
  
  <p><img src="https://i.stack.imgur.com/0kCEy.png" alt="enter image description here"></p>