

The first link did have different instructions, but it didn’t solve the problem.
I also tried replacing Fcitx with Ibus, the other major IMF that may have better Gnome support. But I have the same problem plus others: on some apps like Firefox, the popup appears in the top left corner instead of where I am typing.
Edit: It is better now, see post edit, but still issue with popup being white on white.
Pas sûr, mais je pense ananas, clémentine et peut-être poire.