title: cocoa NSArrayController show custom wizard on add action
body: <p>I have the <code>NSArrayController</code> and <code>NSTableView</code>, also linked "add" button with add method of <code>NSArrayController</code>. When I clicked the add button - it just create new row at <code>NSTableView</code>.<br>
  I wish to show my custom wizard, where user can input all necessary information. 
  What is the best way to do it?</p>