Configure Steam to work with IBus

Create a local override of the Steam desktop shortcut:

cp /usr/share/applications/steam.desktop ~/.local/share/applications/

Edit the local shortcut. Look for the Exec= lines, add env GTK_IM_MODULE=xim right after Exec=. Example:

# Exec=/usr/bin/steam %U
Exec=env GTK_IM_MODULE=xim /usr/bin/steam %U

Repeat for every one of the Exec=` lines, then save and exit.

Launch steam through the desktop shortcut, and IBus should be working. If not, try forcing an update to the desktop database with:

update-desktop-database ~/.local/share/applications/

Reference

Gemini