For sometime now, my main desktop has been Debian LXDE virtual machine. There is a problem with lxterminal though. Whenever I changed its settings they were not saved. It turns that this is a permission problem. You have to make sure of two things:
Directory ~/.config/lxterminal exists and is owned by you. You may find it owned by root. chown this.
File ~/.config/lxterminal/lxterminal.conf exists and it is owned by you. You may find that it does not exist. Create it using touch.
Managing organized complexity 