Japanese input in Fedora23 – Niels K.
If the folder $HOME/.config/imsettings doesn’t exist, create it first.
And now a bit of background.
I switched for a short time to Ubuntu. My reasoning was that I can give better family support but I switched back to Fedora. Ubuntu was so far the worst Linux experience, at least with my existing configurations. But after switching back to Fedora 23 Japanese input didn’t work. Fedora 23 uses ibus as default method. And it tries to do things automagically and in doing that, they totally failed for me.
There is a script /etc/X11/xinit/xinitrc.d/50-xinput.sh. This script tries to do some magic and works pretty late in the process of starting your GUI when using the default GDM. First it unsets a whole bunch of environment variables and thus will probably anything you set up locally, when you come from another distribution like in $HOME/.xprofile or $HOME/.xinputrc or some other candidate for setting the variables above. Then it looks up if you have $HOME/.config/imsettings/xinputrc. If not, it should create $HOME/.config/imsettings and looks if you have a file $HOME/.xinputrc. If you have it, it gets moved to that folder. And then the file gets sourced and the script is finished.
The folder creation part is the place where I guess the script failed for me.
And if that file doesn’t get sourced by the script for whatever reason, the script looks up which LANG-variable you have set and compares it to a hardcoded list. And then sets up environment variables depending on your LANG-variable.
If you have set en_US.utf8 like me that means that they get set up in a minimal way which leads to not being able to use an IME. And of course the script doesn’t bother logging anything.