Drilling to Content, Drill Through, Cell Attachments and Comments
If a report designer has added Drill to Content links to grid cells, or if drill through to source and/or cell file attachments exist at the data source and have been enabled for viewing in the report, you can click on the links to launch the target report, document, URL, drill through or cell file attachment when you preview the report in HTML.
If more than one drill definition exists for a cell, a drop-down box with all of the definitions is displayed. Click the link that you want to launch to view the target in a separate browser tab.

You can also view the cell notes or text comments attached to the report or grid cells. To view the full note text, ensure that you hover your mouse over the contextual menu.
Here is an example: