The Xserver has three options which controls the maximum lifetime of ThinLinc sessions. These are described below, and can be added to the parameter /vsmagent/xserver_args.
-MaxDisconnectionTime s
Terminate when no client has been connected for s seconds. Note: Never use a value smaller than 60.
-MaxConnectionTime s
Terminate when a client has been connected for s seconds
-MaxIdleTime s
Terminate after s seconds of user inactivity. Note: Never use a value smaller than 60.
In addition to the options above which control the lifetime of the ThinLinc session, the option -IdleTimeout can be used to configure how long an idle session should remain connected. The -IdleTimeout option takes a number of seconds as an argument, and can be added to the parameter /vsmagent/xserver_args as per the options described above.
Setting -IdleTimeout s will simply disconnect the client from the session after s seconds; it will not terminate the ThinLinc session itself.