I first tried a four-year-old solution and then, after it became clear that clicking the keyboard icon of Fcitx was freezing my system via locking up lxpanel, I uninstalled packages as followed under #lubuntu IRC advice:
username@username-Latitude-D620:~$ sudo apt purge fcitx-frontend-gtk3 fcitx-frontend-qt4 fcitx-frontend-qt5 kde-config-fcitx
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package 'kde-config-fcitx' is not installed, so not removed
The following packages were automatically installed and are no longer required:
libaudio2 libfcitx-qt5-1 libmng2 libmysqlclient20 libqt4-dbus libqt4-declarative libqt4-network libqt4-script libqt4-sql libqt4-sql-mysql libqt4-xml
libqt4-xmlpatterns libqtcore4 libqtdbus4 libqtgui4 mysql-common qdbus qt-at-spi qtchooser qtcore4-l10n
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
fcitx-frontend-gtk3* fcitx-frontend-qt4* fcitx-frontend-qt5*
0 upgraded, 0 newly installed, 3 to remove and 7 not upgraded.
After this operation, 390 kB disk space will be freed.
Do you want to continue? [Y/n] Y
(Reading database ... 157746 files and directories currently installed.)
Removing fcitx-frontend-gtk3 (1:4.2.9.6-1) ...
Removing fcitx-frontend-qt4 (1:4.2.9.6-1) ...
Removing fcitx-frontend-qt5:i386 (1.1.1-1build3) ...
Processing triggers for libgtk-3-0:i386 (3.22.30-1ubuntu1) ...
username@username-Latitude-D620:~$ sudo apt autoremove
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
libaudio2 libfcitx-qt5-1 libmng2 libmysqlclient20 libqt4-dbus libqt4-declarative libqt4-network libqt4-script libqt4-sql libqt4-sql-mysql libqt4-xml
libqt4-xmlpatterns libqtcore4 libqtdbus4 libqtgui4 mysql-common qdbus qt-at-spi qtchooser qtcore4-l10n
0 upgraded, 0 newly installed, 20 to remove and 7 not upgraded.
After this operation, 44.8 MB disk space will be freed.
Do you want to continue? [Y/n] Y
(Reading database ... 157733 files and directories currently installed.)
Removing qt-at-spi:i386 (0.4.0-8) ...
Removing libfcitx-qt5-1:i386 (1.1.1-1build3) ...
Removing libqt4-sql-mysql:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing libmysqlclient20:i386 (5.7.24-0ubuntu0.18.04.1) ...
Removing libqt4-dbus:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing qdbus (4:4.8.7+dfsg-7ubuntu1) ...
Removing mysql-common (5.8+1.0.4) ...
Removing qtchooser (64-ga1b6736-5) ...
Removing libqtgui4:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing libaudio2:i386 (1.9.4-6) ...
Removing libmng2:i386 (2.0.2-0ubuntu3) ...
Removing libqt4-declarative:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing libqt4-xmlpatterns:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing libqt4-network:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing libqt4-script:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing libqt4-sql:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing libqtdbus4:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing libqt4-xml:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing libqtcore4:i386 (4:4.8.7+dfsg-7ubuntu1) ...
Removing qtcore4-l10n (4:4.8.7+dfsg-7ubuntu1) ...
Processing triggers for libc-bin (2.27-3ubuntu1) ...
Processing triggers for man-db (2.8.3-2) ...
Reading this Q&A I clicked Preferences > Language Support and installed additional language packages as prompted, i.e. reinstalling the packages I'd just removed:
But I don't have ibus like that other user, only fcitx and XIM. fcitx freezes lxpanel on either the first or second click. What should I do?
It's something related to the skin. Please install fcitx-ui-classic. At first use shortcut to active input method to Chinese (or other instead of the en_US input method), then click the indicator, popup the skin menu, select classic, then the problem will be gone.
I confirm it's the option
in addon → advanced that cause the problem.
Run
fcitx-config-gtk3
to uncheck it.I had a similar issue on Ubuntu Mate 19.10 with the fcitx icon in the Indicator Applet in the panel freezing up the system. I initially thought the problem was fcitx, but it was actually the Indicator Applet, which I eventually removed from the panel. That got rid of the problem for me.