title: Adding loading gif to NSAlert
body: <p>I am wanting to add a loading gif to my NSAlert I have tried this but it does not seem to be working:</p>
  
  <pre><code>NSProgressIndicator * gif;
  gif.style = NSProgressIndicatorSpinningStyle;
  [gif startAnimation:self];
  
  NSAlert *alert = [[NSAlert alloc] init];
  [alert setInformativeText:@"Please check your internet connection and try again."];
  [alert setMessageText:@"Connection Error"];
  [alert setAlertStyle:NSWarningAlertStyle];
  [alert setAccessoryView:gif];
  [alert runModal];
  </code></pre>
  
  <p>Any ideas what I am doing wrong?</p>