Hi,
Prometheus controls suit, part of which is RadToolTip "Prometheus", is based on ASP.NET AJAX framework. ScriptManager is necessary for registering client scripts for Microsoft ASP.NET AJAX and Prometheus controls cannot work without adding the
ScriptManager on the page. More details about Prometheus controls suit you can find
here.
Don't hesitate to contact us again if you have other questions.
Best regards,
Sophy
the Telerik team