Linked columns: showing a field from a related table — Seeing the records behind a number

Click any rolled-up number in the grid — a linked column that counts or totals, or an ordinary Rollup field — and the records it was made from open in a list, each showing what it contributed. Click one to open it; Back returns to the list. If the number only counts some records, you get exactly those, because it's the same working-out that produced the number rather than a fresh guess at it. The list is also current: a record that has changed since the page loaded shows as it is now.