bug#7398: 23.2.90; Missing descenders in menu and toolbar tooltips

[Eli Zaretskii]

> Date: Sun, 14 Nov 2010 20:18:28 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: f.j.wright@live.co.uk, 7398@debbugs.gnu.org
> 
> > From: "Drew Adams" <drew.adams@oracle.com>
> > Date: Sun, 14 Nov 2010 06:05:14 -0800
> > Cc: 
> > 
> > > This is on Microsoft Windows 7.
> > 
> > Confirmed also for Windows XP.
> 
> It is part of a larger problem with Emacs tooltips on MS-Windows: we
> somehow miscalculate the dimensions of the tooltip.  You can see that
> even with the default font, if you slowly move the mouse pointer from
> left to right above the mode line: some of the tooltips that pop up
> have truncated text.
> 
> There's a TODO comment about this in w32fns.c:x-show-tip.
> 
> FWIW, this problem exists at least since Emacs 23.1.

I believe I solved this now (on emacs-23 branch; the trunk needs a
slightly different solution, due to bidi display, to follow shortly).