[winswitch] Strange read-only mounts on lubuntu 18.04

[Antoine Martin]

(snip)
> But when I enter exactly the same command into a terminal window on the
> same machine but provided by an Xpra session, the results are quite
> different and surprising:
(snip)

> Note that all my usual mounts are read-only, not read-write, and there
> are strange new mount points not seen before. The read-only attribute
> interferes with the normal operation of many standard applications. The
> disk /dev/sda on the machine running the Xpra is healthy. I can repeat
> the direct inquiry via ssh shown first and get the same results any time
> *after* seeing the anomalous report coming through Xpra.
> 
> I am mystified. Any proposed explanations and/or remedies for this
> situation (even me-too reports) would be most welcome. Thanks!    - Philip
In order to better isolate individual sessions from the rest of the
system, we use the system-wide proxy server to register them as proper
systemd sessions. This includes setting "ProtectSystem" to "strict", for
more details see:
http://lists.devloop.org.uk/pipermail/shifter-users/2017-August/001990.html

Cheers
Antoine