In Lubuntu I can change the default applications using "Default applications for LXSession" application. It saves the default application list in the configuration file "/home/USER/.config/lxsession/Lubuntu/desktop.conf". Now, I'd like to change default applications by editing this "desktop.conf" file. So, I change/save the "desktop.conf" file or overwrite it with the one from another machine. But when I re-open "Default applications for LXSession". it does not show the changes made in the "desktop.conf" file and therefore the default applications are not set.
How can I change the default applications using the configuration file? Do I need to run any update/reset command after editing the file?