bug#40687: Missing right border on composed text used in 'display property

[Eli Zaretskii]

> From: Stephen Berman <stephen.berman@gmx.net>
> Cc: Clément Pit-Claudel <cpitclaudel@gmail.com>,
>   40687@debbugs.gnu.org
> Date: Thu, 23 Apr 2020 22:07:21 +0200
> 
> > FTR, a recipe to test more fully display of composed text with a :box
> > face is below.  I found quite a few problems with this, especially
> > when the text in the boxed face ends with a composed character.  They
> > should be fixed now on the master branch.  I tested this fully only on
> > MS-Windows; could someone please use the recipe below to verify the
> > display looks correctly also on X and on NS?
> 
> I'm on GNU/Linux and confirm that with your patch all the buttons
> produced by your recipe display correctly, i.e., with the right border.

Thanks for testing, much appreciated.