Can't display help-echo in overlay string with composition.

[YAMAMOTO Mitsuharu]

"Arg out of range 0,0" repeatedly occurs when trying to display
help-echo string in an overlay string with composition.

 1. emacs -Q -D
 2. (overlay-put (make-overlay 1 1) 'before-string
                 (propertize (compose-string "ab") 'help-echo "ab"))
 3. Move the mouse pointer to the beginning of buffer.

                                     YAMAMOTO Mitsuharu
                                address@hidden 


In GNU Emacs 22.0.50.1 (sparc-sun-solaris2.8, X toolkit, Xaw3d scroll bars)
 of 2006-05-31 on church
X server distributor `AT&T Laboratories Cambridge', version 11.0.3332
configured using `configure '--x-libraries=/usr/local/lib' 'CFLAGS=-g -O2 -mv8 
-DSYNC_INPUT''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: ja
  locale-coding-system: japanese-iso-8bit
  default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  line-number-mode: t