Could some kind soul point me in right direction for an explanation of what this does.
Option appears permanently 'greyed out' an inoperable.
When you are viewing two images at once, either side-by-side or above and below, you can enter zoom mode and pan each image independently. Once you have particular details aligned, using the Lock scrolling causes panning in one image to occur simultaneously in the other image. It makes it really easy to compare details between two images. For instance in portraits, you might want to see if someone's eyes were closed, or if the sharpness is better between two images.
BTW, all of this is explained in the manual which is available in the Announcements section of the forums.
HTH,
-Kirk
