title: Rebar control, what causes a RBN_AUTOBREAK notification to be sent
body: <p>One of the notifications sent by a rebar control is RBN_AUTOBREAK.  </p>
  
  <p>I have a generic event handler for a rebar control and I want to test for RBN_AUTOBREAK.  But, I can't figure out how to get the control to send that notification.  Does anyone know what combination of things would cause the notification to be sent?</p>