Markups and Notes
Use
In the Information panel, there are also options relating to the display of markup and note information, if the file that you are viewing contains them. For markups to be displayed on an image or model, the Show Markups option must be selected on the Information panel. The icon pertaining to markups acts as an on or off toggle.
Features
If you want to view markup information, click the 
icon on the Information panel.