Update Gateway after changes to SSAS

I have a Enterprise Gateway installed with SSAS(Dimensional model), and a dataset created in PowerBI from the gateway.

I've added a dimension to my cube and referenced from fact table.  I deployed, and processed the cube. I can browse it in the SSAS instance and see the changes.

I cannot see the new dimension in PowerBI.

If I choose to Refresh the dataset, it tells me "This dataset connects to a SQL Server Analysis Services Tabular database & is always up to date. You don't have to schedule a refresh on this dataset."

How do I get PowerBI to reflect changes made to SSAS structure?