bug#139: describe-key vs. widget red tape

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Mon, 30 Sep 2019 07:56:58 +0200
> Cc: 139@debbugs.gnu.org
> 
> >     <down-mouse-1> at that spot runs the command widget-button-click
> >       which is an interactive compiled Lisp function in `wid-edit.el'.
> >     It is bound to <down-mouse-1>, <down-mouse-2>.
> >     (widget-button-click EVENT)
> 
> [...]
> 
> > Nope. The only way to find out what will happen is to fasten one's
> > seat belts and hit or click and find out.
> >
> > And even if there is a different incantation to find out, describe-key
> > should also cough up the ultimate answer too.
> 
> I don't think there's any way that could work in general.  Emacs knows
> what down-mouse-1 calls, but it doesn't know about what that function in
> turn does.
> 
> We could teach describe-key about certain common constructs, like
> widgets and buttons, but that would be very ad hoc indeed, I think?

If the action of the button is not clear from the button's label, it
should have a help-echo string which describes that.