bug#12204: 24.1.50; Binding mouse-movement interferes with "C-h c" for mouse clicks

[Eli Zaretskii <eliz@gnu.org>]

> From: npostavs@users.sourceforge.net
> Cc: 12204@debbugs.gnu.org
> Date: Sun, 11 Jun 2017 20:18:54 -0400
> 
> > This happens because gud-tooltip-mode binds the command
> > gud-tooltip-mouse-motion to mouse-movement event.  The echo area
> > display of "C-h c" about that is promptly erased by the next mouse
> > motion, so if you are going for a tool bar or menu bar, you won't
> > notice it.  Then you will be surprised by the execution of a command
> > for which you wanted to see help.
> >
> > This is not a bug, strictly speaking: the help command works as
> > designed.  But I wonder whether we could somehow surprise the user
> > less in this situation.
> 
> Perhaps describe-key could respect 'use-dialog-box' and popup a dialog
> box when the "key" comes from the mouse?

What would be shown in the dialog box?