Let's say I press W, and then I stop pressing it, or press another letter
Let's say I press W, and then I stop pressing it, or press another letter
Setting the environmental variable to 2 or 0 completely fixed the input lag for me, as the @fansari also reported above. There are a lot of methods to do that, but I personally prefer the modular one, using the profile.d:
File /etc/profile.d/90-ibus-lag-fix.sh
Enable ibus hybrid asynchronous processing
export IBUS_ENABLE_SYNC_MODE=2

