I have an application that calls -[WebView becomeFirstResponder] and it's throwing an exception: NSWindow: -_oldFirstResponderBeforeBecoming is not a valid message outside of a responder's implementation of -becomeFirstResponder. The call to -_oldFirstResponderBeforeBecoming was added in <http://trac.webkit.org/projects/webkit/changeset/21367>.
<rdar://problem/5451537>
Darin says that becomesFirstResponder is meant to be called by AppKit and not directly by applications. Applications should call makeFirstResponder with the object. Please reopen if you disagree