title: Disable Option-Enter line breaks in NSTextField?
body: <p>I want to disallow entering a new-line character in my NSTextField, which by default is possible by typing Option-Enter (or Option-Return).</p>
  
  <p>While I found <a href="http://developer.apple.com/qa/qa2006/qa1454.html" rel="nofollow noreferrer">some</a> <a href="http://developer.apple.com/DOCUMENTATION/Cocoa/Conceptual/TextEditing/Tasks/FieldEditor.html" rel="nofollow noreferrer">pages</a> explaining how to <em>allow</em> line breaks <em>without</em> having to use the Option modifier, I couldn't find anything for <em>disabling</em> line breaks altogether.</p>
  
  <p>How can this be done?</p>