bug#23092: 25.0.92; Minibuffer completion fails to resize completion window if reused during same command

[N. Jackson]

At 22:10 +0200 on Tuesday 2016-03-22, Eli Zaretskii wrote:

>> From: nljlistbox2@gmail.com (N. Jackson)
>> Date: Tue, 22 Mar 2016 16:56:03 -0300
>> Cc: 23092@debbugs.gnu.org
>> 
>> > displaying two, three completions in a window that occupies one half
>> > of your frame does not strike me as a good solution either.
>> 
>> For me though, this seems absolutely fine. After all that window is only
>> there until I've finished my command in the minibuffer, then it
>> disappears.
>
> In theory, yes.  In practice, it's all too easy to cause it be left in
> place long after you have no use for that buffer.  I'm sure it
> happened to you at least once.

Actually, no, I haven't had that problem yet, not caused by the
completions window at least; it seems to consistently close when I
finish the command in the minibuffer.

>> (If it was taking up so much space that it prevented me from seeing
>> something I needed to refer to while completing my command in the
>> minibuffer, that would be another matter entirely, but with the
>> completions window occupying the right half of the frame that was never
>> an issue for me in Emacs 24.)
>
> Having it occupy half the frame, obscuring too much of the buffer I'm
> editing, is also an annoyance.

Yes, obscuring the buffer being edited is an annoyance. I suppose the
circumstances when it occurs depends on the user's set up.

In my usage I almost always use a small laptop and the display is
sufficiently small that it's easiest to keep all my Emacs frames
maximised. The display has a 16:9 rather than a 4:3 (16:12) ratio, so
I'm rather limited in height compared to width. A full height window
here is only 48 characters high.

When my frame gets split-right, I get two windows that are both about 92
characters wide, so a completions window on the right rarely obscures
_any_ of the window I'm editing (which is typically displaying lines of
text 72- or 80-characters long).

On the other hand, the new behaviour of splitting the completion window
below is guaranteed to obscure part of the window I'm editing.