[winswitch] Can't start xpra session

[Anthony Stone]

Antoine,

I am puzzled by the following. I tried to start an xpra session on my
usual server, and got this on the client:

 $ xpra start ssh/whirligig/100 --start="gnome-terminal
--window-with-profile=Blue" &
[3] 21295
17:57:38 $ 2018-08-29 17:57:39,090 Xpra gtk2 client version 2.3.3-r20112
64-bit
2018-08-29 17:57:39,090  running on Linux Ubuntu 16.04 xenial
...etc...
xpra initialization error:
 failed to identify the new server display!
2018-08-29 17:58:02,443 Error: failed to receive anything, not an xpra
server?
2018-08-29 17:58:02,443   could also be the wrong protocol, username,
password or port
2018-08-29 17:58:02,444   or the session was not found


So in an ssh session on the server, I tried the following:

17:59:57 $ xpra list
Found the following xpra sessions:
/run/user/1013/xpra:
	UNKNOWN session at :100
/home/ajs1/.xpra:
	UNKNOWN session at :100
/run/xpra:
	UNKNOWN session at :100
Re-probing unknown sessions in: /run/xpra, /home/ajs1/.xpra,
/run/user/1013/xpra
	UNKNOWN session at :100 (cleaned up)
	UNKNOWN session at :100 (cleaned up)
	UNKNOWN session at :100 (cleaned up)
18:00:13 $ xpra stop :100
xpra initialization error:
 cannot find live server for display :100
18:00:30 $ xpra stop
xpra initialization error:
 cannot find any live servers to connect to
18:00:37 $ xpra list
No xpra sessions found

and then tried to start a session from the client as before, using the
same command, and I got the same initialization error. Going back to the
server, I got, much as before,

18:00:45 $ xpra list
Found the following xpra sessions:
/run/user/1013/xpra:
	UNKNOWN session at :100
/home/ajs1/.xpra:
	UNKNOWN session at :100
/run/xpra:
	UNKNOWN session at :100
Re-probing unknown sessions in: /run/xpra, /home/ajs1/.xpra,
/run/user/1013/xpra
	UNKNOWN session at :100 (cleaned up)
	UNKNOWN session at :100 (cleaned up)
	UNKNOWN session at :100 (cleaned up)
18:01:43 $
18:12:36 $
18:12:36 $ xpra list
No xpra sessions found

Am I doing something daft, or is there a bug? The xpra start command has
worked many times before -- I usually use ctrl-R to retrieve the
previous start command each time, rather than retyping it.

On both server and client, I have:
 $ xpra --version
xpra v2.3.3-r20112


Anthony Stone