How to "Reset" an unbound dimension which has a flat list.

Summary:

Using "viewpoint" load for a flat list unbound dimension does not get rid of the nodes I no longer want in my viewpoint. How can I reset it without having to register this as a bound dimension just to load the metadata again.

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):