Apparently I was using Stephan Wessels' button from the IRC Enhancements
CS; it's enclosed here.

from preamble:

"Change Set:		RadioButtonGroupMorph-nk
Date:			25 July 2002
Author:			Ned Konz

This is a simple radio button group that takes a single target and sets
buttons based on the return value of performing a selector on that
target.

See the class side for examples of its use.

It includes the UpdatingThreePhaseButtonMorphEnhanced from Stephan B.
Wessels' IRC Enhancements change set.

RadioButtonGroupMorph example1
"!
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