bug#50670: 28.0.50; Conflict on minibuffer indicator overlays

[Eli Zaretskii]

> From: Gabriel <gabriel376@hotmail.com>
> Date: Sun, 19 Sep 2021 02:59:19 -0300
> 
> Apparently, there is a conflict between the overlays of
> 'minibuffer-depth-indicate-mode' and 'icomplete-mode' when inside
> recursive minibuffers.
> 
> Steps
> 1) emacs -Q from master branch
> 2) eval:
>     (setq enable-recursive-minibuffers t)
>     (minibuffer-depth-indicate-mode 1)
>     (setq icomplete-scroll t
>           icomplete-show-matches-on-no-input nil)
>     (icomplete-vertical-mode 1)
> 3) C-x f multiple times to go into recursive minibuffers
> 
> The 'minibuffer-depth-indicate-mode' overlay "[%s]" is rendered on
> the right side of 'icomplete-mode' overlay "%s/%s" momentarily, and then
> it moves to the left side (the correct position). The problem can also
> be reproduced when the minibuffer input changes, e.g., by typing
> 'C-x f' + 'backspace'.

FWIW, I see only the latter, when I type Backspace.

Doesn't this happen because both mb-depth.el and icomplete.el put
overlays with before-string on the same position, minibuffer's BOB?