Hi,
1. If you want to have drilldown enabeld, you need to have more then one category.
2. If you are creating chart document, you already have drilldown for BAR chart. For PIE it will be available in next release.
3. If you are creating cockpit, inside edit mode you need to change arrow icon to filter icon. It will disable cockpit selection and enable drilldown. It is possible for BAR chart. For PIE it will be available in next release.

