openbox-session runs an openbox session without any session manager. Without a session manager, you will not be able to save your state from one log in to the next.
openbox-session does not take any command line arguments.
On log in, openbox-session will run the
~/.config/openbox/autostart script if it exists, and will run the
system-wide script /etc/xdg/openbox/autostart otherwise. You may
place anything you want to run automatically in those files, for example:
xsetroot -solid grey & gnome-settings-daemon &
Make sure that each line is followed by a "&" or else the script will stop there and further commands will not be executed. You can use the /etc/xdg/openbox/autostart file as an example for creating your own.