Cascading / Dependent dropdown

[wcaulker]

It would be very useful to have a cascading dropdown  visual option, as opposed to multiple dropdowns. For example, to be able to select or hover over a region, and then for the region's constituent Counries or offices to display as filter options. This can currently be achieved using third party developer's visualizations, but it would be very useful, especially as space is often limited on a report page.