bug#10464: 24.0.92; mouse highlight regression

[Chong Yidong]

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.


In GNU Emacs 24.0.92.9 (x86_64-unknown-linux-gnu, GTK+ Version 3.2.0)
 of 2012-01-09 on furball
Windowing system distributor `The X.Org Foundation', version 11.0.11004000
configured using `configure  '--with-x-toolkit=gtk3' 'CFLAGS=-g''