bug#25906: 25.1; strange behavior of overlapped mouse-face

[Eli Zaretskii]

> From: npostavs@users.sourceforge.net
> Cc: ynyaaa@gmail.com,  25906@debbugs.gnu.org
> Date: Wed, 01 Mar 2017 18:37:17 -0500
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: ynyaaa@gmail.com
> >> Date: Wed, 01 Mar 2017 12:44:36 +0900
> >> 
> >> 
> >> Evaluating the form below, then move the mouse cursor on the inserted text.
> >> When it is on aaa, underline is displayed on aaaBBB as expected.
> >> When it is on ccc, overline is displayed on BBBccc as expected.
> >> 
> >> When it is moved holizontally from aaa to BBB, overline is not displayed.
> >> When it is moved holizontally from ccc to BBB, underline is not displayed.
> >
> > I cannot reproduce this on my system.  Here the underline is displayed
> > no matter how I move the mouse pointer.
> 
> I can reproduce on Windows 10 and GNU/Linux, from at least Emacs 24.3 (I
> don't currently have an earlier working build).

Ah, I think I've misunderstood what is exactly strange in the
behavior.  Please describe what was expected in each case, so we are
sure we are on the same page.