bug#11651: Special display is not dedicated any more

[martin rudalics]

> Something's wrong with the way the `dedicated' bit is set:
>
>   % src/emacs -Q --eval '(setq special-display-regexps (quote ("\\*.*\\*")))'
>   C-h v values RET
>   M-: (window-dedicated-p nil) RET
>   q
>
> The M-: shows that the window is not marked dedicated as it should.
> And the `q' shows the consequence: rather than hiding the frame, Emacs
> switches to some other buffer.
>
> This was probably introduced in the last couple weeks.

Indeed.  I was fooled by a comment in `special-display-popup-frame'.
The old code had

       (let* ((frame
               (with-current-buffer buffer
                 (make-frame (append args special-display-frame-alist))))
              (window (frame-selected-window frame)))
         (display-buffer-record-window 'frame window buffer)
         ;; FIXME: Use window--display-buffer-2?
         (set-window-buffer window buffer)
         ;; Reset list of WINDOW's previous buffers to nil.
         (set-window-prev-buffers window nil)
         (set-window-dedicated-p window t)
         window)))))

but `make-frame' already puts BUFFER into the new frame so the
`set-window-buffer' is silly.  I changed this to

       (let ((frame
              (with-current-buffer buffer
                (make-frame (append args special-display-frame-alist)))))
         (window--display-buffer
          buffer (frame-selected-window frame) 'frame t))))))

but `window--display-buffer' detected that BUFFER was already displayed
in the new window and decided not to deal with it.

Can you try replacing the snippet by

       (let* ((frame
               (with-current-buffer buffer
                 (make-frame (append args special-display-frame-alist))))
              (window (frame-selected-window frame)))
         (display-buffer-record-window 'frame window buffer)
         (set-window-dedicated-p window t)
         window)))))

martin