Re: `insert' deactivates active region

["Richard M. Stallman" <rms@xxxxxxx>]

    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.

This is not a bug.  Modifying the buffer deactivates the mark.