Today, I wrote on G+ before seeing you already responded here and already implemented the stuff!
¡Si, señor, olé!
I'm running 3.5.1. The issue happens for Private Pages and Files when editing an existing item:
When creating a new item (
/wp-admin/post-new.php) it opens ok.
Re: Private File Category
I haven't updated to your new commit, I'll take a look afterwards and report back.
Yes, I'll surely review and would appreciate yours as well ;)
Take a look at this Easy Digital Downloads thread, it is affecting your plugin too.