Handling minibuffers in several mini-windows

[Alan Mackenzie <acm@muc.de>]

Hello, Emacs.

This post probably belongs in the thread "Stop frames stealing
eachothers' minibuffers!", but I think people are beginning to suffer
thread-fatigue wrt that thread.  Only Martin R. is currently posting
things to me in that thread.  (Thanks, Martin!)

The problem arises when minibuffer-follows-selected-frame is configured
to nil, thus allowing several mini-windows to be simultaneously visible
in several frames.  As long as the user attempts to use only the most
deeply nested MB, that isn't a problem, but when she tries to type into,
terminate, or abort another MB, we've got to decide how to handle it.

My proposal (which I've already implemented and tried out, though not
published at all), is that
(i) it should be possible to type into, and edit text in any visible
  minibuffer;
(ii) it should be possible to terminate (by RET `exit-minibuffer') only
  the most deeply nested MB.  The attempt elsewhere should display an
  error message, leaving the MBs unchanged;
(iii) it should be possible to abort (with C-g `abort-recursive-edit'),
  any minibuffer.  This will have the effect of aborting all more deeply
  nested MBs at the same time.

What do people think about this?

-- 
Alan Mackenzie (Nuremberg, Germany).