Well, all your other settings are at zero, are they not? You can't see any changes until you actualyl let the algorithm modify your image...
Yup, at first I thought of that problem, but it isn't really related to it.
The edge detection itself is an algorithm that interpret the transition area specified by the radius to reconfirm the edge of the object and the background.
Im not sure about it, but just roughly know it from this video:
You're correct. Adjusting the Edge Detection Radius slider should be changing the mask edge, of course, regardless of other settings being zero.
Something strange in your images is that the Quick Mask button near bottom of Tools bar is depressed. I don't know how or why that is. For me (Ps 13.0.5 on OS X), Refine Mask and Quick Mask are mutually exclusive - RM cannot be activated while QM is active, and QM cannot be activated while RM is active.
Something strange in your images is that the Quick Mask button near bottom of Tools bar is depressed.
Messing around a bit I found both QM and Refine Mask can be active (target mask, open Channels Panel, enter QM, then target the alpha channel mask - now enter Refine Mask. This should get to state where Tan is) and I get the same problem with Refine Edge radius control.
Tan: exit Refine Mask. Hit the Q key (to exit Quick Mask) and try Refine Mask dialog again.
Good sleuthing by Charles!
Nice one, Conroy and Charles. It solved my problem.