bug#61296: 28.2; Curious depth indicator behavior with icomplete-vertical-mode

[Eli Zaretskii]

> From: Fernando de Morais <fernandodemorais.jf@gmail.com>
> Date: Sun, 05 Feb 2023 10:15:54 -0300
> 
> 1. Evaluate the following snippet:
> 
>   (progn
>     (with-eval-after-load 'icomplete
>       (customize-set-variable 'enable-recursive-minibuffers t)
>       (customize-set-variable 'icomplete-show-matches-on-no-input t)
>       (setq icomplete-scroll t)
>       (minibuffer-depth-indicate-mode 1))
>     (icomplete-vertical-mode))
> 
> 2. C-x C-f
> 3. M-x
> 4. Then C-n (`icomplete-forward-completions'); wait a moment; C-n again.
> 
> Results in:
> 
>   - The depth indicator and the `icomplete' current/total number of
>     matches keep swapping places with each other in the prompt prefix
>     area.

I can reproduce this in Emacs 28.2, but not in Emacs 29.  So I guess
we already fixed this bug somehow since Emacs 28.2 was released.