Highlighting is a way to call attention to a subset of data in a view. There are three types of highlighting on Tableau Server: Individual Selection, Legend Highlighting, and Highlight Actions.
When you select one or more marks in a view, all other marks are dimmed so that your selection stands out. Select individual marks or click and drag the pointer to select a bunch of marks. Hold the Ctrl key on your keyboard to select multiple marks in the view.
You can use the legends (color, shape, and size) to highlight the marks that correspond to each item in the legend. For example, if a view is colored by product category, you can quickly highlight a certain type of product using legend highlighting.
Click the Highlight button that displays in the upper right corner when you rest the pointer over the legend.
Select an item in the legend.
You can hold the Ctrl key on your keyboard to select multiple items in the legend. Turn legend highlighting off by selecting the Highlight button again.
Some views may have Highlight Actions, which highlight related data in one or more views based on your selection in a source view. Highlight Actions are primarily used in dashboard views where multiple views are shown at once. For example, in the dashboard view below there is a highlight action set up to highlight on product category. When the Office Supplies category is selected in the bar chart all the other views highlight the office supplies category.
Depending on the how the view was authored, Highlight Actions can be launched either by selecting a mark, resting the pointer over a mark, or in the screen tip that displays when you rest the pointer over a mark for a period of time.