I ran into a problem on my Angtergos+Openbox.
Whenever I download stuff on Firefox and click the “open containing folder”, it opend with audacious for some reason. I wanted to change this in my ‘preferred applications’ but it won’t open.

when I run on terminal $ lxsession-default-apps I get:

/home/odedi/.gtkrc-2.0:19: Unable to find include file: "~/.gtkrc-2.0.mine"
** Message: main.vala:592: log directory: /home/odedi/.cache/lxsession-default-apps
** Message: main.vala:593: log path: /home/odedi/.cache/lxsession-default-apps/run.log
Aborted (core dumped)

The ERROR I see in the mentioned log is:

ERROR:lxsession-default-apps/autostart.c:637:ldefault_apps_manual_autostart_init: assertion failed: (stream != null)

I don’t understand what causes that. I also tried to configure it using xdg-tools but I found it too complicated, so if that’s the way to do it, I’d love to get some kind of guidence.
Thanks to all helpers and of course to the excellent dev of this project