Comments mark up documents and can document threaded discussions.
You can:
- Add comments (and reply to comments)
- Add text and other elements with markup tools
- Edit and delete comments
Comments are listed in the order they were added on the markup comments tree on the Markup pane.
Viewing Comments
In model files, you can view only one comment at a time because different comments may apply to different model states.
In drawing files, all comments for the active sheet are visible simultaneously.
Graphical indicators notify you if a comment is associated to a markup 
.
Active Comments
To activate a comment, select the comment on the
Markup pane. Only one comment can be active at a time.
- The active comment icon is green.
- Unread comments are bold.
Markup items are added to the active comment.
- In model files, you must activate a comment before you can view or edit the comment.
- In drawing files, you can view or edit all comments, including inactive comments, but only the active comment is highlighted in the graphics area.