Input methods in GTK4 apps on Wayland

🫧 Open on Bubbles When trying to type using an input method on GTK4 it simply doesn’t work. The same input methods work on GTK3, Qt5, Qt6, and a variety of other applications which don’t use any of these toolkits. GTK4 is the sole outlier. Running with WAYLAND_DEBUG=1 reveals that GTK4 applications don’t even try to bind to the zwp_text_input_manager_v3 global. A peek through GTK4’s code indicates that the default input method backend is simple, which is really a pseudo-backend which means “don’t use any in