Re: delete-overlay causes recentering

[Richard Stallman]

      When the filling command has reformatted the buffer text, the
      redisplay code still starts window display at the old window start
      -- which still is in the middle of a line, but not at the same
      relative position in the line as before ... so it gets confused.

      This is just one way in which a buffer change can mess things up
      when window start is not at the start of a line, so I think it is
      generally a bit difficult to find a method which will always select
      the intuitively best window start after such a change.

In that case, it is supposed to recenter.  However, the bug of
spurious recentering occurs when the buffer has not been changed at
all.  It should be easy to distinguish that case and recognize that
there is no need to recenter.


In any case, the bug is not fixed.  I observed it after C-c C-c to
send a message, in an Emacs I built yesterday which has your fix in
it.