Linux Mint 18.3 KDE 64bit
kubuntu 18.04.1 LTS, 64 bit
Lenovo Thinkpad 230; Japanese keyboard

I simply love the KDE activities because they fit very well my way of working. Unfortunately Linux Mint 19 does not have a KDE DE anymore; I hope for the future and installed 18.3 KDE

For Japanese communication I need to switch back and forth between Japanese and English. In my Lenovo X240, also with Japanese keyboard, I have LM 17.3 KDE 64 bit running and IBUS-Anthy works without any problem. Setup was a "5-minute affair".

In Linux Mint 19 Cinnamon and Xfce IBUS-MOZC is running fine as well. MOZC has a little drawback compared to Anthy. Thus I prefer Anthy.

In the, on top mentioned KDE versions, IBUS-Anthy is not working at all. I even compared package by package with the packages installed at my x240, LM 17.3 machine.

In all cases, the Japanese keyboard is working correct. All keys show up as normal (normal input is Latin characters, Arabic numbers and all the special characters).

When I click the "zenkaku-hankaku" key (for non-Japanese keyboards usually Ctrl+Space key is used) of my Japanese keyboard, IBUS is changing the logo for Latin characters and Japanese characters in the system tray. However Japanese characters are not displayed.

I now assume that the problem is in the new KDE Plasma versions.

I appreciate a lot your help. I am newbie concerning commands but once I know the commands I can handle them.