RE: Fix some tooltip related problems

[Drew Adams <drew.adams@oracle.com>]

> > (x-show-tip (propertize "abc" 'face '(:foreground "gray")))
> >
> > What's different here from what you are talking about?
> > OK, I'm using MS Windows.  But does this not work also
> > on GNU/Linux and Mac?
> 
> This doesn’t work on the NS port. Tooltips on that platform are
> neither system tooltips nor fully‐fledged frames. I think it also
> doesn’t work with certain X toolkits (GTK?) where they use system
> tooltips.

I see.

> > And if that doesn't work on such platforms, can't we use
> > a ("normal") Emacs frame where such things do work?  Just
> > what is it that makes it impossible for Emacs to dim the
> > text in a tooltip?  Sorry, but this is not clear to me.
> 
> It’s beyond me why you’d want to dim a tooltip. Dimming of menu items
> is standard behaviour on many platforms whereas dimming a tooltip is,
> afaik, a completely novel behaviour and as a result would just be
> confusing.

1. The ability to use different Emacs faces in a tooltip
   frame is much more general than the use of that ability
   to dim the text in a tooltip.  It's a general feature.

   I didn't realize that Emacs was so limited in this regard
   on other platforms.  Thank goodness it works without a
   problem on at least some platforms (e.g. Windows).

   Given that limitation, I repeat the question: Can't we
   use a ("normal") Emacs frame, where things such as faces
   do work, to implement tooltips?

2. Wrt dimming a tooltip to show that its text, or some of it,
   applies generally, or at least in some contexts, but does
   not apply currently:

   The argument that we shouldn't do it because that would be
   "novel" isn't a good argument.  That a feature is "novel" is
   an argument neither for nor against its being added to Emacs.

   Emacs has, from the beginning, done things that weren't
   mainstream or even, yes, that were completely novel.
   There are some Emacs features that are still not found
   outside Emacs even though they've been in Emacs for decades.

   Ask yourself: How did dimming of menu items become standard
   behavior?  How did that feature ever get added to anything?
   Certainly not by someone who argued that it shouldn't be
   added because it is "novel" or is not yet standard.

   Did someone have to explain to you what a dimmed menu item
   is all about?  Is that inherently confusing the first time
   someone sees it?  I think not.  A tooltip with dimmed text
   is no more confusing.