The functionality of the server is incomplete wrt use of the "newpage" directive. It is not possible to view all the "pages" of the resulting diagram(s), and the server does not generate the diagrams as documented in the User Manual.
The server should display the diagrams as shown in the User Manual. Next best would be to update the User Manual to describe the current behavior properly, and perhaps some better guidance in the UI when this is occurring, but this is a significant feature that really should work properly from the server. Current behavior is at best confusing and at worst a bug.