I've got an early 2013 Macbook pro Retina. Until recently I was using bootcamp to use windows, but I found Parallels actually gave a better experience, so I've been using OSX more and more. Periodically, after it wakes up or returns from the screen saver being active, it changes to "Scaled" rather than "best for retina".
How do I stop it from switching to "scaled"? I'd like to keep it on "Best for retina" at all times.