Is there maybe a Problem with the retina display?
The problem is probably rather that Photoshop CS6 is not ready to take full advantage of that display.
A Forum search should point to some threads on the issue.
Mr. Frampton wrote:
But why do I not have this problem with Lightroom?
Because Lightroom is partially Retina-ready. Its Open dialog is one of the parts that is Retina-ready.
Post 38 in this thread
seems to address some of this.
But you could also ask over at the Lightroom Forum.
Anyway, I guess you are just using a piece of hardware that was probably not even available to Adobe when Photoshop CS6 was being developped.
As we can tell just from the screen shots, the image on the left (from Photoshop) is larger than the one on the right (from Lightroom). The exact same pixels are being used in each, but the pixels are larger, which is a Retina compensation. Both of these dialogs are created by the OS, not by either Photoshop or Lightroom.
But the problem should be fully addressed by installing the 13.0.2 update for Photoshop.