bug#55712: the fix for this broke the ability to paste into gmail plain text

[Eli Zaretskii]

> From: Tom Gillespie <tgbugs@gmail.com>
> Date: Tue, 9 Aug 2022 21:10:00 -0700
> 
> I have a bug where emacs can no longer paste into gmail
> compose windows that are set to plain text, and the fix for
> this bug 03b780e387e54c23ac9322e329aca6e5ab4f18e6
> bisected as the bad commit. Reverting the commit resolves
> the issue.
> 
> The issue is on linux under X11 on master at all points after
> 03b780. To reproduce, copy some text from emacs and try
> to paste it into a gmail compose window that is set to plain
> text mode.
> 
> I do not know exactly which part of the changes induced the
> behavior, but reverting the commit clearly fixes the issue and
> allows me to paste into plain text mode compose again.

Hard to understand how completion could be related to pasting.

Could you please run the modified code under Edebug, put a breakpoint
where that commit made changes, and show the Lisp backtrace when that
breakpoint is hit?  Maybe that will give us some hints.

Thanks.