How to create an interactive dashboard that only shows related entries when key is selected?

I’m trying to create a dashboard where I can see all relevant information pertaining to a district and site at once. I don’t like that when no district is selected, all the sites and service tickets are visible.

When a district is selected it only shows the relevant info.

When no district is selected, I see all sites and service tickets. I would like for service tickets and sites view to be blank.

Does anyone know how to fix this to only show relevant information to the district?

You can enter in a “blank” record (but make sure the key value isn’t blank), for the child Tables, and make sure it is the first record that Appsheet loads. For GSheets, this would mean that it would be on the 2nd row, for a SQL database it would mean the key value comes first alphabetically. This is the record that the dashboard displays when nothing is selected.