This dashboard is designed to give a single year snapshot of procurement by a country. Advanced cross-filtering is therefore disabled. However, you can use other dashboard such as the procurement overview dashboard if further filtering is desired.
The Procurement by category chart shows data at the highest category level (UNSPSC segment). Right click on the category chart and select "Drill up" to see the category information by ASR Sector. Data on more detailed category levels is available on the Categories page.