Hi,
Is tailf:display-when only applicable to cli and Web UI, and not to Netconf interface
Yes, from the User Guide:
tailf:display-when condition
The argument contains an XPath expression which specifies when the node should be displayed in the CLI and WebUI. For example, when the CLI performs completion, and one of the candidates is a node with a ‘display-when’ expression, the expression is evaluated by the CLI. If the XPath expression evaluates to true, the node is shown as a possible completion candidate, otherwise not.