bug#29478: [Patch] bug#29478: 26.0.90; `C-h k' followed by mouse clicks no longer shows down event

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: acm@muc.de,  29478@debbugs.gnu.org,  npostavs@users.sourceforge.net
> Date: Tue, 02 Jan 2018 22:56:55 -0500
> 
> > This patch doesn't apply to the master branch, so I couldn't test it.
> 
> It was meant to be read rather than to be applied.

Sorry, I'm not good at reading such large patches.

> If you want a patch that applies, the one below should work.

Thanks.  It needs some more work.  E.g., "C-h k C-mouse-1" signals an
error:

  help-fns--analyze-function: Symbol’s function definition is void: nil

and "C-h k C-mouse-3" followed by a menu selection asks for another
key or mouse click, although it already has got a full key sequence.

In general, I see the idea is to show both down-mouse-N event and
mouse-N event, both with "C-h c" and "C-h k".  That could be okay, but
why show undefined sequences?  E.g, "C-h c S-mouse-1" shows this in
the echo area:

  <S-down-mouse-1> at that spot runs the command mouse-appearance-menu
  <S-mouse-1> at that spot is undefined

I'd expect the second line not to appear.

Also, if both events are bound, I think we should show the mouse-N
event before the down-mouse-N event, because the former is much more
important and normally is the one that's bound.

Thanks.