bug#74590: 31.0.50 [scratch/igc branch]; key input sometimes skip fcitx input method preedit box

[Eli Zaretskii <eliz@gnu.org>]

> Cc: Gerd Möllmann <gerd.moellmann@gmail.com>,
>  Helmut Eller <eller.helmut@gmail.com>, 74590@debbugs.gnu.org
> Date: Mon, 02 Dec 2024 16:26:50 +0000
> From:  Pip Cet via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> "Yikai Zhao" <yikai@z1k.dev> writes:
> 
> > I have reproduced the issue with your patch, here's the relevant log:
> 
> Thank you! So it seems we call XFilterEvent correctly but it incorrectly
> indicates that the keypress (event 2) should be handled by Emacs rather
> than the input method. That's rather puzzling, particularly since
> subsequent calls to XFilterEvent return 1, indicating that the key
> release is handled by the input method.
> 
> I'm pretty much stumped at this point. It might be a timing difference
> between the MPS and non-MPS builds, but I think it's more likely to be
> a bug in our MPS code.
> 
> > Please let me know if there's any other info I can provide.
> 
> Well, you already tried setting x-gtk-use-native-input to t :-)
> 
> One thing you could try is to run a full x11trace of the Emacs session
> and see whether anything unusual is in there. But that's not guaranteed
> to yield any results.

Maybe Po Lu (CC'ed) could have some additional ideas or comments.