Viewer: When clicking into the image it zooms to 100%.
I propose the addition of a ZOOM OUT to fit functionality for the case when one has 100% set.( Z pressed)
PS CS6 implements this by clicking into the enlarged image while holding the H key.
The click alone can not be used since it is required for panning.
Purpose of this functionality is to give the viewer a quick overview of what he is looking at in detail.