Empty dashboard (no data) when user filter value is unselected

We are trying to build a dashboard to display charts and tables that will help us to analyze the sales history for a selected customer.

In the “User Filter” selection box of the dashboard, the Zoho Report’s user should first select the desired customer’s name (filter the list by name), and then all the charts and tables will display information that belongs only to the selected customer.

What value could we add on the “Default Filter Value” of the “User Filter” menu, so no data is displayed as default?

Now, when we select “[NONE]” on the “Default Filter Value” configuration field, the data from all customers is displayed on the dashboard (we want an empty dashboard until a specific customer is selected).

Thanks!