>>> If I eval

>>

>>> (progn
>>> (setq pop-up-frames t)
>>> (display-buffer "*Group*"))

>>

>>> The *Group* buffer will be displayed in a new window, but no new frame
>>> will be created.

>>
>> That's not what I see with the trunk of Emacs-CVS startd with "emacs
>> -Q", so either it's been fixed, or it depends on some config of yours.

> The error is on my side. :-)

> I use my own `display-buffer-function' to have emacs split windows
> horizontally by default. And, of course, I forgot to handle the
> pop-up-frames case. Now I tried adding it, but I don't get it right. How
> do I create a new frame and display a given buffer in it?