[winswitch] Strange read-only mounts on lubuntu 18.04

[Philip Loewen]

Here's a strange experience using xpra v2.3.1-r19531 as the server on a 
new installation of lubuntu 18.04. This is a fresh installation from the 
xpra.org repos.

Here at my remote location, I can connect to the machine that serves 
Xpra using a direct ssh connection (not the Xpra client) and check my 
mounts. The results are unsurprising:

$ mount | grep /dev/sd | sort
/dev/sda1 on / type ext4 (rw,noatime,errors=remount-ro,stripe=32734,data=ordered)
/dev/sda3 on /boot/efi type vfat (rw,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
/dev/sda4 on /16.04 type ext4 (rw,noatime,data=ordered)

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:

$ mount | grep /dev/sd | sort
/dev/sda1 on /home type ext4 (rw,noatime,errors=remount-ro,stripe=32734,data=ordered)
/dev/sda1 on /root type ext4 (rw,noatime,errors=remount-ro,stripe=32734,data=ordered)
/dev/sda1 on /tmp type ext4 (rw,noatime,errors=remount-ro,stripe=32734,data=ordered)
/dev/sda1 on / type ext4 (ro,noatime,errors=remount-ro,stripe=32734,data=ordered)
/dev/sda3 on /boot/efi type vfat (ro,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
/dev/sda4 on /16.04 type ext4 (ro,noatime,data=ordered)

(The terminal application is lxterminal 0.3.1.)

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