Telnet cluster connection can't be edit

[I2OIM]

In my setup the form "Cluster management", tab "Connection" is black and withe (no color). In manual it is coloured.
I cant add a "Known server" to the "Active servers" list, and I can't edit a server.
I can create a "user defined" server, but I can't add it to the active servers list.
I imagine it is a stupid trick I didn't find in the manual...

Thanks for any help!

Pietro I2OIM

screenshot:
https://www.dropbox.com/scl/fi/5m838lmq ... 1kjfm&dl=0

[G4POP]

Stop the Telnet client to edit/add all in the user guide!