bug#10464: 24.0.92; mouse highlight regression

[Eli Zaretskii]

> From: Chong Yidong <cyd@gnu.org>
> Date: Mon, 09 Jan 2012 18:16:38 +0800
> 
> With latest trunk, the (non-automated) redisplay testsuite is failing in
> Test 2.  Here is a simplified recipe:
> 
> emacs -Q
> 
> Insert the following:
> 
>   (let ((opoint (point))
>       overlay)
>     (insert "XXX")
>     (setq overlay (make-overlay opoint (point)))
>     (overlay-put overlay 'display "XXX")
>     (overlay-put overlay 'mouse-face 'highlight))
> 
> M-x eval-buffer RET
> Move the mouse over the XXX that was inserted.
> 
> Result: multiple lines are highlighted, from the end of the first buffer
> line to the end of the display string.
> 
> Expected result (works in Emacs 23): only the XXX is highlighted.

I think I fixed this (trunk revision 106827), but please test,
including any variations on this theme you can come up with.  The
bidi-aware mouse highlight is tricky business, especially when display
strings are involved.