Re: `buffer-list' and the frame-parameter `buffer-predicate'

[Richard Stallman]

    for all the rest of my editing. The effect of my mode should be that
    all functions for buffer-listing or buffer-switching in the Gnus-frame
    show only resp. apply only to the *Group*, *Summary*, *Article* and
    the message-buffers, while exactly those buffer are not visible in the
    other frame. In other words: it would seem as if Gnus were running in
    a separate instance of Emacs, while, of course, it still _is_ the same
    instance with all the benefits implied by this.

Do you mean that C-x b would hide the existence of other buffers?
Would it simply refuse to show them in completion?
Would it refuse to switch to them if you specify their names?
What about C-x C-b?

The other question is, why is this feature useful?  If you want to use
a certain frame only for Gnus, you could simply choose not to switch
to any other buffer in that frame.  If that is not a sufficient
solution to the problem, could you tell me why not?

    The big, big problem is that this bypasses functions like
    `save-buffers-kill-emacs', too. And exactly this makes it unusable.

Why is that a problem?  It seems like a feature to me.

I guess the question is, are you trying to improve your own
convenience as a user, or are you trying to create a mode which will
truly "fool" a user into thinking that two separate Emacses are running?