Install fcitx-module-x11 by entering the following commands in the terminal:
sudo apt update sudo apt install fcitx-module-x11
Description:
Flexible Input Method Framework - X11 module and XIM frontend
Fcitx is a input method framework with extension support, which provides an interface for entering characters of different scripts in applications using a variety of mapping systems. . It offers a pleasant and modern experience, with intuitive graphical configuration tools and customizable skins and mapping tables. It is highly modularized and extensible, with GTK+ 2/3 and Qt4 IM Modules, support for UIs based on Fbterm, pure Xlib, GTK+, or KDE, and a developer-friendly API. . This package provides the X11 module, X11 utilities used by other addons such as fcitx-ui-classic, and is required for all desktop users. An Xlibs based virtual keyboard module has been also included in this package for it's an obvious feature needed by many desktop users. . XIM frontend (client) is placed in this package too because of its nature of being the basic input protocol supported by X.
Homepage: https://github.com/fcitx/fcitx
Version: 1:4.2.9.6-1
Section: universe/utils