title: Cocoa NSTextField value not changed
body: <p>I created <code>NSTextfield</code> programmatically:</p>
  
  <pre><code>func createText(point:NSPoint) {
          let txtFld = AnnotationTextField(frame: NSMakeRect(point.x, point.y, 360,40))
          txtFld.isEnabled = true
          txtFld.delegate = self
          self.contentView.addSubview(txtFld)
          txtFields.append(txtFld)
  
          txtFld.becomeFirstResponder()
      }
  </code></pre>
  
  <p>But when I click on another field or hit <code>Enter</code> key, my string not saving.</p>
  
  <p><a href="https://i.stack.imgur.com/4SQQy.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4SQQy.gif" alt="enter image description here"></a></p>