Subject: bug#745: pop-to-buffer, frames, and input focus

From: martin rudalics <[email-masked]>
Date: Wed, 20 Aug 2008 22:56:58 +0200

> Are you saying, that pop-to-buffer can't be used to select the window,
 > the frame, and input focus at the same time?  If so, when should
 > pop-to-buffer be used?  Aren't that unusual situations when
 > pop-to-buffer should not also select the input focus?

With emacs -Q evaluating

(let ((pop-up-frames t)
       (buffer (get-buffer-create "foo")))
   (pop-to-buffer buffer))

here gets me a new frame on top of the previously selected one, the
window displaying buffer `foo' is the selected window, and when I now
start typing, characters get displayed in that window.  What did you
expect and what did you get?

 > If you have any hints or guidelines how be a good buffer/window/frame
 > citizen in different scenarios, that would be much appreciated.

I'm slightly confused because in your earlier scenario you bemoaned the
fact that the frame _was_ selected.  All I wanted to say that raising a
frame, giving it input focus, and _not_ selecting it might be difficult.

 > I'm not using multiple frames myself, but I'm maintaining a package
 > called SLIME[*] which is used by a number of people who use frames.  I'm
 > not excited at all about rewriting a dozen or so uses of pop-to-buffer
 > just to support multiple frames.  There are some variables like
 > display-buffer-reuse-frames and special-display-buffer-names and I hoped
 > that those variables were supposed to make it easy to support multiple
 > frames without cluttering the source code.
 >
 > [*] http://www.common-lisp.net/project/slime/

I moved `pop-to-buffer' to window.el so you can easier try to play
around with it and propose a solution that fits your needs ;-)

 > The docstring of display-buffer reads
 > "Make buffer BUFFER-OR-NAME appear in some window but don't select it. ..."
 > I think it be would less surprising if the input focus would not be switched
 > to the new frame.

You have a point here but it's not up to me to decide that.

 > If I do
 >
 >    emacs -Q -nw --eval '(save-window-excursion
 >                           (let ((pop-up-frames t))
 >                             (display-buffer (get-buffer-create "foo"))))'
 >
 > I end up in the "*scratch*" buffer not in "foo". It would be more
 > consistent if the X11 version and the tty version would restore the
 > input focus to the same frame.  The tty version is the behavior that I
 > would expect.

When I do

(save-window-excursion
   (let ((pop-up-frames t))
     (display-buffer (get-buffer-create "foo"))))

in the *scratch* buffer I end up in `foo' - whether this is TRT I don't
know.  Doing a `save-window-excursion' on the command line is beyond my
comprehension.

martin