RE: Where to show message output while inputting [was: New multi-command facility displays in the wrong echo area]

[Gregory Heytings via "Emacs development discussions." <emacs-devel@gnu.org>]

>>> The same problem will exist if you move output (`message' echoes) to 
>>> the mode-line: you won't be able to see the mode-line info and the 
>>> message at the same time.
>>
>> That's obviously a problem that will exist in any possible solution to 
>> that problem: the message will hide something.
>
> Not if the area used for echoes (output) is separate from the area used 
> for the minibuffer (prompt and input).
>

I meant: it will hide something on screen.  For example with a 
conventional pop-up it would hide a part of a buffer.

>
> But we need not overwrite - or displace at all, if we show the output in 
> its own area - at least when there would otherwise be a conflict with 
> the minibuffer/echo area.  I mentioned "popping up" such an output area 
> as needed.
>

Yes, that's the idea of temporariy adding a "zeroth" / "minusoneth" line 
to the miniwindow in which the message would be shown.  But it will still 
hide something, namely another line in that frame.

>
> Shifting existing stuff around could be distracting or annoying for some 
> users.
>

It's what eldoc already does for a similar situation, and I haven't seen 
complaints about this.  IMO it's elegant to solve that problem in that 
way.

BTW, if you don't shift the contents of the mode-line, you shift the 
contents of the buffer(s) above the mode-line.  Which could also be 
distracting or annoying, because such a shift could imply a temporary 
recentering of these buffers in their windows, when point is on their last 
line.