ToggleButtonCallbacks (Radio behavior)

[Fred]

When I have two toggle buttons in a RowColumn that has
XmNradioBehavior set to True, and register a valueChanged callback on
each button, everything works fine when switching from one button to
the other:
I first get a callback on the button being unset (with cbs->set having
a value of False.
Then I get a callback on the button being set (with cbs->set having a
value of True).

But when the user clicks on the button that is currently set, I would
really expect no callbacks at all, since neither button has had its
state changed.

However, that is not what happens. I get TWO callbacks on the button
being re-pressed, both with cbs->set == True.

So why do I get TWO valueChanged callbacks on the same widget when the
value has not changed?

--
Fred K