Java applications display issues

Applications that are built with Java may sometimes not load correctly. If it happens, it might be because you changed the window manager name at the end of your configuration file:

# XXX: Gasp! We're lying here. In fact, nobody really uses or cares about this
# string besides java UI toolkits; you can see several discussions on the
# mailing lists, GitHub issues, and other WM documentation that suggest setting
# this string if your java app doesn't work correctly. We may as well just lie
# and say that we're a working one by default.
#
# We choose LG3D to maximize irony: it is a 3D non-reparenting WM written in
# java that happens to be on java's whitelist.
wmname = "LG3D"

Setting wmname = "LG3D" will allow Java application to load correctly.

The (minor) problem with using this "LG3D" string is that neofetch or similar tools will use it to name your window manager. If like me you are proud of using Qtile, you really want neofetch to print qtile and not something else.

Well, there is a solution.

You have to export the environment variable _JAVA_AWT_WM_NONREPARENTING with a value of 1 before launching your Java application.

In Bash it is done with export _JAVA_AWT_WM_NONREPARENTING=1.

You can either export this variable in the beginning of a wrapper script that launches the Java application, or export it globally when the system starts up.

For example, see this /usr/bin/pycharm wrapper script:

#!/usr/bin/env bash
export _JAVA_AWT_WM_NONREPARENTING=1
/path/to/pycharm-community-2019.2.1/bin/pycharm.sh

For more information, see issues #558 and #1189