Kirk,
In Beta 10, when going from contact sheet display to full screen display, the image shows only in landscape mode, turning portrait-mode images on their side. I tried from both catalog and file folder, and both do the same thing. I have only NEF and JPG images; format does not make a difference.
Also, in full screen mode, the rotation buttons at the top of the screen do nothing to the image.
This is new behavior in Beta 10.
Thanks,
-- Ken