Re: flyspell bug

[Richard M. Stallman]

    I often wondered why there are no hooks associated with switching
    buffers, windows, and frames.

These activities are too low level.  Certainly in the past it was not
safe to run Lisp code for switching buffers, and maybe not for windows
either.  Nowadays, since Lisp code can run during redisplay, maybe
it would be safe.  But I do not like the idea.  Do you really want
set-buffer to run Lisp code you don't know about?