Hi there Peter thanks for reaching posting in the Lucidchart Community! Unfortunately this feature is only available for our web application-- I apologize for the confusion I understand that the option still shows as being available. If you take a look at Lucidchart OnPrem for Confluence article it goes through what features aren't available in our OnPrem application.

However we're always looking for ways to improve OnPrem and your feedback is the best way for us to do that. If you think it would be beneficial to add this feature mind adding your idea to our feature request form? Ideas submitted to this form are passed on to the product development team for their consideration.

Thanks for your request and I apologize for any inconvenience this causes you.