> 1. Whatever the client (Windows or Linux 4.0.3.1-4), the local environment
> variables are not set properly and the software - which needs French
> localization - crashes. That could be "solved" the following way :
> /etc/x2go/Xsession :

Hmm, the environment is usually set by the system. Is a local session
working properly?

Yes, local sessions are working properly.

An application that crashes because of missing locale vars is 100% buggy.

Let's say 80% buggy :-)

> 2. At the start of a new session, one gets a windows with an error message
> "No session for pid ..." ; that bug has already been reported several times
> in x2go bug tracking and marked as solved. Actually it is not on my brand
> new system.

I have no idea about this, except: Maybe there are some relicts of a
previous version of x2go. It could help to manually remove all nx and
x2go related packages completely, clean the filesystem for remains and
retry,

I mixed it out : it was reported in LXDE mailing list. In my case it happens only in combination with x2go (fresh install, without any nx mixup).

> 3. The single application mode does not work with some of the applications,
> including that Laurux / Gambas. For example it works with /usr/bin/leafpad,
> but /usr/bin/libreoffice makes the x2go session crash.

There are applications that fork themselves and return immediately,
which in turn causes the session to close down because there's no
client left. Please check if running xterm in single application mode
and starting those applications from there is working.

x2go full session : xterm then /usr/bin/libreoffice -> works

x2go single application mode /usr/bin/xterm -> got the xterm, but typing /usr/bin/libreoffice closes the session

Uli