Tooltip is represented with the  icon.

Any field that you drop on Tooltip is added to the tooltip box. The fields in the tooltip are always aggregated. However, you can still add a Dimension to the tooltip. Tableau uses a special aggregation, ATTR, to display it. This aggregation returns the value if it's unique, or shows * if not. That symbol means that there is more than one value.

Clicking on the Tooltip button opens a window where you can edit the text and change a few options. Those options allow you to:

• Choose whether you want to show the Tooltip
• Include the command buttons (Keep Only, Exclude, Group, Set, and so on) or not
• Allow selection by category or not

Here's an example of Tooltip use:

You can also add other Worksheets in the Tooltip. This functionality is called Viz in Tooltip. In the Tooltip editing window, you have the option to insert objects on the top-left. Here, it's possible to select a Worksheet. You can modify the width, height, and filters of the Viz in Tooltip. Here's an example of a Viz in Tooltip:

The next property, Shape, is only available with the Mark type of the same name.