Re: New multi-command facility displays in the wrong echo area.

[Gregory Heytings]

Hi Stefan,

> > > (i) In a GUI environment, create two frames, each displaying a buffer.
> > > (ii) In frame F1, do C-x b `switch-to-buffer', but don't type anything more.
> > > (iii) Move to frame F2, and start an isearch with C-s some-text.
> > >
> > > Although currently in F2, the isearch's pattern is displayed in the 
> > > echo area for F1.  This is wrong.
> >
> > FWIW, this behavior has been with us at least since Emacs-21.
>
> I fear that's not correct.  I don't see this behavior in Emacs 21 to 26 
> (inclusive), it is new in Emacs 27.1.  More precisely, it is because the 
> new variable set-message-function has the default value 
> set-minibuffer-message. To restore the previous default behavior:
>
> (setq set-message-function nil)

IMO this could/should be fixed in set-minibuffer-message, by checking that 
the active minibuffer is on the same frame:

(when (and (not noninteractive)
           (window-live-p (active-minibuffer-window))
           (eq (window-frame) (window-frame (active-minibuffer-window))))