i am working on Screensurfer session management, doing all 
my tests in SS DevCenter.

if i open two SS sessions, log on the mainframe and try  to 
switch between sessions,
i can see the last screen of the selected SS session, but 
after submitting, often get "...SECURITY VIOLATION..... 
OPERATOR NOT SIGNED-ON...." screen.
this means that i lose my mainframe session and need to log 
on again.

this does not happen with all screens. 
from some screens i can continue navigation without errors.
with single session everything works fine.

do you know what might kill the mainframe session of an 
open SS session? could it be the mainframe configuration?
(SS connects directly to the mainframe)

There might be a limit in the mainframe security system on 
how many sessions your USERID can be logged-on to 
concurrently, like 1.

Or, you might be timing-out...some systems will give this 
kind of message following a timeout.

Can you try with a single session just leaving it for a 
while, then hit it to see if this appears?

i just tried lo leave session for about 1 hour: no error.
it seems to be happening to particular pages and only if 
you switch from one session to another.

i use one username/password to log on and normally can open 
all five sessions.