bug#27427: 26.0.50; Native line numbers lead to display error in company-mode popup

[Eli Zaretskii]

> Date: Thu, 29 Jun 2017 09:17:41 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: dgutov@yandex.ru, alexanderm@web.de, 27427@debbugs.gnu.org
> 
> So the answer to your question is: We can supply any restrictions the
> TTY display code would need although I'd prefer to call this a "special
> kind of frame" and not a "special kind of window".

I prefer "window" for the simple reason that doing so will most
probably wreak the least havoc on TTY display, in particular because
it won't invalidate the assumption that only one frame is visible at
any given time.  Also, frames can have decorations, even on a TTY,
which we are better without in this case.  And finally, you most
probably remember that TTY redisplay is frame-based, so having just
one of them would fit better.

Should be a nice project.  Any takers?