I'm not the person you were replying to, but here's the straw that broke this multilingual camel's back: unless Gnome is running under Wayland, switching the keyboard layout steals the input focus away from the foreground window briefly, causing focus-loss event handlers to fire. This might seem an easily fixable minor issue but it's actually a decade-old hairball which significantly harms the experience and can't be fixed cleanly under X.
I didn't notice Wayland becoming the default, tbh. Thanks for mentioning this.
As for the specific bug, it was introduced by the implementation of a non-essential feature (the languague switch HUD) which was then left in place, likely because the Wayland transition was juuust around the corner. While Wayland does address many architectural issues, I don't think X users should deal with regressions caused by Wayland-optimized features just yet (and definitely not 8 or so years ago).
