bug#57423: Completions Buffer requiring window switching or mouse activity

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 26 Aug 2022 03:18:58 +0200 (CEST)
> From: wilnerthomas--- via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> 
> Using  "M-x COMMAND TAB"  to display minibuffer commands, one gets a 
> temporary Completions Buffer that says
> 
> Click on a completion to select it
> 
> Consequently, one cannot complete or go through the possibilities in the minibuffer, 
> but am being forced to either switch to it with "C-x o" a couple of times, or having
>  to use the mouse.

You don't need to switch or use the mouse.  You can instead:

  . keep typing TAB to scroll through the full list of completion
    candidates (if the full list takes more than a single window to
    show), or
  . type more text in the minibuffer, then press TAB again, to narrow
    the list of candidates -- the next letter which will narrow the
    list is displayed in bold in the list of the candidates, or
  . in Emacs 29, you can type M-<UP> and M-<DOWN> arrow keys to select
    the candidates

> An effective way that improves the frequent minibuffer activity (e.g. icomplete lets user
> select a completion without having to smitch windows), emacs can automatically switch
> to the completions buffer so one can get to a possible selection using the arrow keys.

In Emacs 29, there's a new variable 'completion-auto-select', which
does precisely that.