RE: on helm substantial differences

[Drew Adams]

> Features wanted in ivy or icomplete or anything inside
> of Emacs or in GNU ELPA:
> 
> - full frame completion with mode line staying where it is
> - split window completion as helm does it, with mode line
>   staying where it should be

And you mentioned vertical presentation of candidates.

FWIW, Icicles offers that.  You can show candidates
vertically, in a single column *Completions*, if you set
option `icicle-Completions-max-columns' to 1.

There are many kinds of completion, and many kinds of
completion candidates.  For short candidates, a single
column wastes an incredible amount of screen real estate.

That may be fine, if your only purpose is to narrow to
a particular candidate.  But if you're operating on or
otherwise examining the _set_ of current matches in some
way, then you likely want to see more than just a few of
them, and being able to show more than one on a single
line helps a lot.

On-the-fly filtering is about many things.  What's
really involved is manipulating a candidate _set_.
For that, it helps to see most or all of the set.

The design of Icicles recognizes this high degree of
variability in candidates (including display size) and
in uses of filtering and manipulations of a set of
candidates.

In particular, you can change the *Completions* display
on the fly, if you also use library Do Re Mi, just by
using `C-x w' or `C-x |' in the minibuffer, followed by
arrow keys or mouse wheel to increment and decrement the
values of options `icicle-inter-candidate-min-spaces' and
`icicle-candidate-width-factor'.  That is, you can
incrementally change how many columns of candidates are
displayed (`C-x w') and the space used between candidates
(`C-x |').

If all kinds of candidates looked basically similar, then
there'd be no need to be able to tweak the display on the
fly.  And yes, many kinds of candidates do look basically
similar (function names, buffer names, etc.), so you don't
need to change the display often.  But when it makes sense
to do so, you can easily do it, immediately.

https://www.emacswiki.org/emacs/Icicles_-_Completions_Display