In Tableau, how does a dashboard filter action differ from a highlight action?

## The shared plumbing Dashboard actions in Tableau are defined under Dashboard > Actions (or from the caret menu of a sheet). Every action, whatever its type, has: - one or more **source sheets** the interaction starts from, - a **trigger**: run on **Hover**, on **Select**, or on **Menu** (a link in the tooltip), - **target sheets**, - a field mapping: **All Fields** (match on every field the two views share) or **Selected Fields** (an explicit source-field to target-field mapping). The types differ in what they do to the targets: Filter, Highlight, Go to URL, Go to Sheet, Change Parameter, Change Set Values. ## What a filter action does A filter action takes the dimension values on the mark you interacted with and applies them as a filter on the target sheets. Select a bar for the West region and every target sheet is now restricted to West. The consequences are the ones interviewers probe: - **The targets re-query.** Each target worksheet sends new queries to its data source. Eight targets means eight sets of queries per click, which is the usual root of a sluggish dashboard. - **Aggregates change.** Totals, averages, percent-of-total table calculations, reference lines, trend lines and forecasts all recompute over the filtered rows, because they are computed after filtering. - **Axes rescale.** With Automatic axes, filtering to one small category can make a chart look dramatically different from its unfiltered self. Fixing axis ranges is the usual counter-measure when that flicker is confusing. - **Marks disappear.** The reader loses the comparison set; they can no longer see how the selection compares with its peers. - **The empty-target case must be configured.** What happens when the user deselects is a separate setting on the action, and the default is not always what you want. A filter action behaves like a dimension filter on the target sheet. That matters for one classic surprise: a FIXED level-of-detail calculation is computed before dimension filters, so a value produced by one can appear not to respond to the click at all unless the filtered field is added to context. ## What a highlight action does A highlight action leaves the target's data alone. Every mark the target had is still drawn; marks whose values match the source selection stay at full colour and the rest are dimmed. Nothing is filtered away, so totals, axes, reference lines and table calculations are unchanged, and the reader keeps the full comparison set on screen. Because it operates on marks that are already rendered, highlighting feels instantaneous compared with filtering. The requirement is that the target view actually contains the field being matched on — in the view or on the Marks card — otherwise there is nothing to match and nothing highlights. Highlighting is also available without an action at all, through the highlighter control on a discrete field, which is often the simpler answer when only one sheet is involved. ## Choosing between them Ask what question the interaction answers. - *"How does this one compare with the others?"* — highlight. Removing the others destroys the comparison. - *"Show me only the rows behind this bar."* — filter, usually into a detail table or a secondary chart. - *"I want both."* — a common pattern is highlight across the peer charts and filter only the detail sheet, configured as two actions from the same source with different target lists. ## Configuration details worth knowing The funnel icon on a worksheet in a dashboard — **Use as Filter** — is a shortcut that generates a filter action running on Select from that sheet to every other sheet on the dashboard, matching on All Fields. It is convenient and it is also how dashboards accidentally become slow and over-coupled: every sheet re-queries on every click. Opening Dashboard > Actions and narrowing the target list is the standard cleanup. Run-on-Hover feels responsive for highlight actions and is usually a mistake for filter actions, because merely moving the mouse across a chart triggers query storms and makes the dashboard feel jumpy. Run on Menu is the gentlest trigger: nothing fires until the user clicks a link in the tooltip, which suits expensive targets and drill-through to another dashboard. Finally, a filter action is not the same thing as a filter card. A filter card is a control the reader manipulates directly; an action is an interaction driven by clicking a mark on another sheet. They can conflict — a target sheet can carry both, and the reader sees the intersection of the two.