bug#16767: 24.3.50; `C-x 5 b' for special-display buffers

[martin rudalics]

> So it seems this is not the culprit.

The "culprit" is `special-display-popup-frame' with its

    (let ((window (get-buffer-window buffer 0)))

and it worked this way already in the past century (it had

  (let ((window (get-buffer-window buffer t)))

then).  All this is explained in the doc-string of
`switch-to-buffer-other-frame' as

  By default, if the buffer is already
  displayed (even in the current frame), that window is selected.
  If the buffer isn't displayed in any frame, a new frame is popped
  up and the buffer is displayed there.

So the bug seems rather that C-x 5 b with `special-display-regexps' nil
pops up a new frame when the buffer already appears on some frame.

martin