As they are not always visible, tooltips are an easily overlooked aspect of visualizations. However, they add a subtle professionalism. Consider the following default tooltip that displays when the end user hovers over one of the marks shown in the preceding screenshot:

Compare it to this tooltip:

The tooltip was edited by clicking Tooltip on the Marks card, which brought up an editor allowing for the rich editing of text in the tooltip:

This editor is similar to those used for editing the text of labels, titles, captions, and annotations. You can input text and format it as desired. Additionally, the Edit Tooltip dialog has some additional functionality:

• The Insert drop-down menu in the upper-right corner allows you to insert sheets, fields, parameters, and other dynamic values. These special or dynamic text objects are enclosed as a tag in the text editor (for example, <SUM(Sales)>). We'll take a look at the special case of sheets in a moment.
• A checkbox option to Show tooltips and a drop-down menu to indicate the style of the Tooltip (Responsive - show tooltips instantly or On Hover). 
• A checkbox option to Include command buttons. This is the default, and you can observe the command buttons in the first, unedited tooltip in this section. The command buttons include options such as Include, Exclude, Create Sets, and so on. Many of these options are still available to the end user via a right-click, so removing them from the tooltip does not prevent the user from accessing them completely.
• A checkbox option to allow selection by category. When enabled, this feature allows users to click the values of dimensions shown in the tooltip and thus select all marks associated with that value in the view.