Wrong display and hang with zero-length overlay display string

[Ralf Angeli]

On MS Windows the following code will generate a buffer which displays
"aaa" and after that a lot of whitespace.  If you scroll around a bit
Emacs will hang with 100% CPU usage.  Typing `C-g' does not help.

(progn
  (pop-to-buffer (get-buffer-create "*test*"))
  (insert "aaa\nbbb\nccc\n")
  (let ((ov (make-overlay 5 8)))
    (overlay-put ov 'display "")))

On X11 the code works correctly and displays

aaa

ccc

-- 
Ralf