For the session manager, I also have some other ideas.
Is it possible for lxsession to expose an interface for client tools to change environment variables.
For example, clients can ask lxsession to do setenv("http_proxy", ...), so later newly launched applications will use new proxy settings.
We can also use this to change locale settings on the fly.
Of course, there should be some limitations and some environment variables should not be changeable.
Is this possible?