bug#50067: Context menus

[Eli Zaretskii <eliz@gnu.org>]

> From: Juri Linkov <juri@linkov.net>
> Cc: mattiase@acm.org,  50067@debbugs.gnu.org,  homeros.misasa@gmail.com,
>   tkk@misasa.okayama-u.ac.jp,  larsi@gnus.org,  alan@idiocy.org
> Date: Thu, 19 Aug 2021 10:12:54 +0300
> 
> > OK, but as I wrote elsewhere, I think the string should always be
> > present, and if some GUI toolkit wants to ignore it, it should avoid
> > putting it into the native menu structure when it creates the menu
> > widget(s).  The Lisp data should remain the same, IMO.
> 
> GUI toolkits can't ignore titles for all menus.  Some menus should be
> displayed with a title for all toolkits.

Which popup menus have titles that cannot be ignored, and why?

> The context menu is special.  Nowadays everyone is accustomed to
> down-mouse-3 popping up a context menu without title.  But other
> Emacs-specific menus that are not familiar to users such as
> mouse-buffer-menu bound C-<down-mouse-1> should display a title for
> all toolkits to explain to the user what choice the menu presents.

If we want some titles to behave in special ways, we could put a text
property on the title string to mark those titles that should get
special treatment.  That is better than removing the title, and
certainly better than removing it based on the frame type, because
then Lisp code which handles the menu keymaps will need to be prepared
to handle both kinds of menu keymaps, the ones with a title and ones
without it.  It is also against the documented practice.

So let's please reinstate the title, and use properties or some other
mechanism to mark the title strings that need special handling in some
circumstances.

Thanks.