bug#3145: 23.0.92; detaching GTK+ tool bar crashes emacs --daemon

(This is my fourth attempt to get this into the bugtracker.  On the hope
that there was something about the email body and not my address that
was objectionable, I am omitting the backtrace now.  If this email gets
through, I'll try following up with the backtrace.  Whether or not that
succeeds, the backtrace is available at
<http://lists.gnu.org/archive/html/emacs-devel/2009-04/msg00496.html>
and <http://permalink.gmane.org/gmane.emacs.devel/110453>.)

Carrying out the following steps reliably crashes Emacs:

1. emacs -Q --daemon
2. emacsclient -c
3. Detach the tool bar (only possible with GTK+ build).
4. Close the client frame with C-x 5 0
5. emacsclient -c
6. Detach the tool bar
=> SIGSEGV

If I do not start with --daemon or if I skip either step 3 or step 4,
there is no crash.

In GNU Emacs 23.0.92.2 (i686-pc-linux-gnu, GTK+ Version 2.14.4)
 of 2009-04-23 on escher
Windowing system distributor `The X.Org Foundation', version 11.0.10502000
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: en_US.UTF-8
  value of $XMODIFIERS: @im=local
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t