External Documentation not working anymore

External documentation is greyed out and quick documentation only shows generic information - I've somehow lost access to the XCode documentation.

I think this happened with the XCode 4.6 updatd. Xcode 4.6 install removed the ios 6.0 documentation and added a new iOS 6.1 documentation - perhaps it's related to that?! Maybe it's still looking for the 6.0 documentation?

Is there any way to reset or re-configure the external documentation for a project? should I delete the library/caches/appCode.10 folder?

AppCode 1.6.4 (latest available)