Drill down in dashboards

Dear Gurus,

we have SAP ECC system, SAP BW system and SAP BI(BO) system.

Now the data flow is as given below,

ECC ---> BW ---> BEX query(Datasource for my BO dashboard).

I always use the BEx query as my data source for my dashboard.

Here is a scenario for one KPI, i initially display the count of employees for whole organization and when the user clicks on the chart, it gives count nationality wise.

For this drill down feature i have used "Combo box" (Data Insertion--Insertion type "Filtered Rows"),and the drill down work fine.

My question is, is this the preferred approach for drill down, only "combo box" component must be used? Can we use other components also?

Please share me your ideas.