Howard and Charles -- Thanks.  The reset crop box, whether invoked from the options bar or from the right-click menu, does neither what I wanted, nor what I expected.  (That's not a bad thing; just curious.)

I set the crop box to 13in by 19in then open a landscape image.  It opens with the crop box in place, giving me a portrait crop out of the middle of the image.  I rotate the image using the mouse and delayed shift key so it's in portrait orientation.  The crop box is giving me the middle of the image (not the whole thing).  Fit on screen lets me see the entire image but obviously doesn't alter the crop area.

Resetting the crop box returns the image to landscape orientation.  (Not the result I wanted.)  Here's the quite unexpected part: The reset cleared my crop box specifications.  After resetting, the crop box has been set to unconstrained and is now set to the full size of the image.

I don't consider that a bug -- just a design choice.

Within my experience, the Crop tool is the only one with this kind of "reset" function.  In the classic crop tool, we had the CLEAR button.  The Reset function is implemented the same way.  The difference is that in previous versions, the CLEAR button isn't available once you have drawn the crop box.  Even in CS6, I haven't found any other tool with a Reset option.  So there is no consistency issue.  How Abobe chooses to implement the reset function for the crop tool will become the standard.

And the more I think about this, the more I think Adobe should revisit this decision.  I think it would be more useful -- and more reasonable -- for Reset to return the tool settings to whatever the user had specified at the beginning of the crop operation.

Here's what, to me, is an anomoly in the current implementation: The Reset command doesn't reset ALL of the tool settings.  Reset does not affect "Delete Cropped Pixels" or "Use Classic Mode" or the View setting.