A comment is a Unified Modeling Language (UML) model element that contains comments or textual information. Comments appear in the Model Explorer view and in the diagram editor. In the diagram editor, a comment attachment connects a comment to another diagram element.
You can add a comment to a diagram to provide review feedback or observations about a particular diagram element. If appropriate, you can also attach a single comment to multiple diagram elements.
As the following figure illustrates, a comment is displayed in the diagram editor as a rectangle with a folded upper-right corner, and a comment attachment is displayed as a dashed line that connects the comment to the diagram element.
In the Model Explorer view, a comment is displayed as a small yellow rectangle with a folded upper-right corner. The rectangle contains two horizontal blue lines.