If your dashboard supports drill down, when you place the mouse cursor over the chart, it becomes a hand.
When you click on the graphic you get another graphic that shows more detailed data about the work items you focused on. For example, in a bar chart that shows the work items distribution by process, clicking on a bar leads you to a bar chart that shows the distribution of the work items in that process, grouped by the activity they are sitting in.
You can drill down to the highest level of detail to obtain a list of the work items represented in the chart.
If any of the Work List panels on your page is configured to listen to your chart panel, when you click on a bar or pie of the chart, the Work List panels displays the work items you focused on.