I just stumbled over the plugins cpufreq and netload, which cannot be
pre-configured via rc-files in /etc/xdg/... They just ignore the
XDG_CONFIG_DIRS and create their own private rc-files in $HOME upon the first
configuration by the user.
Said plugins could easily be patched by replacing the calls to
xfce_resource_save_location(*plugin, bool) by
xfce_panel_plugin_lookup_rc_file(*plugin) when reading the plugin settings,
like e.g. cpugraph is already doing. Works fine here.
Possibly other plugins might be affected/could be improved by this as well.
Please provide proper patches and I / the maintainers of the other plugins respectively will apply them.
This enhancement is present on this branch: https://git.xfce.org/users/andre/xfce4-cpufreq-plugin/
After some testing, I will push to master.
Andre Miranda referenced this bugreport in commit 7c820df39ec561cfbce05050e31226e1f78517c4
Use xfce_panel_plugin_lookup_rc_file (Bug #11823)