Clicking this icon opens the Markups dialog, which is used to review markups and comments made in the design.

You can access this tool from the following:

• Ribbon: Drawing > Analyze > Redline
• Ribbon: Drawing > Home > Primary > Key-in drop-down gallery
• Ribbon: Modeling > Home > Primary > Key-in drop-down gallery
• Ribbon: Visualization > Home > Primary > Key-in drop-down gallery
• Toolbox: Primary Tools