`insert' deactivates active region

[Katsumi Yamaoka]

Hi,

Please read and try the following Lisp code.  In the *testing*
buffer, you may see you cannot activate the region by using
C-SPC and C-f, etc.  Furthermore, M-w cannot be used to copy
text, either.

(let ((buffer (get-buffer-create "*testing*")))
  (pop-to-buffer buffer)
  (erase-buffer)
  (insert "Hello World\n")
  (goto-char (point-min))
  (set (make-local-variable 'transient-mark-mode) t)
  (add-hook 'post-command-hook
            (lambda nil
              (with-temp-buffer
                (insert "foo")
                ))
            nil t))

One of the ways to solve the problem I found is to remove the
`(insert "foo")' line.  This problem occurs not only with Emacs
22, but also 21 and 20.  A similar code is used in emacs-w3m and
we are discussing the solution which is effective on all Emacs
versions (there's already a promising solution).

Regards,