bug#18195: 24.3.92; window-screen-lines is not accurate

[Eli Zaretskii]

> Date: Wed, 06 Aug 2014 18:41:21 +0400
> From: Dmitry Gutov <dgutov@yandex.ru>
> CC: 18195@debbugs.gnu.org
> 
> On 08/06/2014 06:39 PM, Eli Zaretskii wrote:
> 
> > That's because the
> > candidates are displayed by Company by putting overlays on consecutive
> > lines of text, each overlay showing one candidate.
> 
> Not really. We have a pull request that changes the code to do what 
> you're describing, but for the moment we only use one overlay at a time.

I'm talking about a kind of menu of candidates, which definitely takes
more than one line.  That cannot be done with a single overlay, unless
you copy the buffer text into the overlay string, and completely cover
the buffer text itself.