You can specify an account options at adding the new account or can change current options of selected account.
Account opions:
Account is disabled - The user account is present and all its settings will be stored, but the user can't will be connected to the Server using this account.
Read only access - The user can only view a desktop. Any commands from the Client will be ignored. Mouse control and keyboard input are disabled.
Only proxy access - This account can use only for proxy connection to another server. This account can't will be used for usual connecting to the current Server.
As a rule one account of this type should be added on a proxy server. It is necessary for users who having an access to computers in local network through proxy server, but not having an access to the proxy server directly.