4.2.2. Custom Tooltips, Visual Interactions, and Sorting
💡 First Principle: Readers explore by hovering and clicking. Tooltips decide what extra context appears on hover; interactions decide how clicking one visual affects the others; sorting decides the order in which values are scanned. Each can be tuned so exploration reveals insight rather than noise.
Default tooltips show the hovered data point's fields; you can add extra fields to a visual's Tooltips well. Report page tooltips go further: create a page, set Page information > Allow use as tooltip to On, set Canvas settings > Type to Tooltip (a small default size), design visuals on it, and add fields to its tooltip fields if you want it to appear for specific fields. Then, on a visual, set Tooltips > Type: Report page and choose the page (or leave Auto to match by field). Hovering shows a mini-report filtered to the hovered data point, such as a trend line for the hovered product.
Edit interactions (select a visual > Format ribbon > Edit interactions) controls how a selection in that visual affects every other visual on the page. Each target visual shows icons:
- Filter: the target shows only data for the selection.
- Highlight: the target shows the selection in context, with the rest dimmed (default for many charts).
- None: the target ignores the selection.
Use None to keep a total card or a reference chart stable when readers click elsewhere, and Filter where highlighting would be confusing (for example, on a line chart). Report settings can change the default from cross-highlight to cross-filter, and allow readers to change interactions.
Sorting: visuals sort by a field or measure using More options > Sort axis (choose the field and ascending or descending). Tables sort by clicking column headers. Chronological ordering of month names requires Sort by column in the model (3.1.1), not a visual sort. A visual can sort only by fields it contains, so to sort by a measure not shown, add it to the tooltips well and then sort by it.
⚠️ Exam Trap: "When users select a region in the map, the total sales card must keep showing the company total" is Edit interactions set to None on the card. Removing the map's Region field or adding a report-level filter doesn't achieve it.
Reflection Question: Why must a report page tooltip be enabled with "Allow use as tooltip," and what determines which data point filters it when a reader hovers?
