Image > Views > Clone

Click the Clone tool to create a 'clone' of the currently active image.  Clones of images allow you to view the same image data in different views, side by side.  For example, you can view the same image data as a normal image, as a 3D representation, and as a surface plot.

Clones are identical to the original, and all changes, adjustments, and enhancements made to the original are applied also to the clones.  The example below shows how LUT adjustment made to the original are reflected in the clone.