title: App crashes after exiting Mail Composer
body: <p>My app is crashing shortly after closing a MFMailComposeViewController.  A UIWebDocumentView is releasing, which deallocates a ComposeBodyField object and it crashes on objc_msgSend.  It only happens some of the time, and only on old devices. I'm assuming that something is being release/cleaned up before it's supposed to, so when the message is sent, the object doesn't exist.</p>
  
  <p>The problem is that I can't get anymore information than that, and I have no idea how any of it ties together.  If anyone can shine some light on this, it would be great.</p>