A key feature of ArgoUML are the critics, which run in parallel with the main ArgoUML tool. When they find a problem, they typically raise a to-do item, and also highlight the problem on the editing pane. The graphical techniques used for highlighting are called Clarifiers
Note icon (). Displayed at the top left of a model element indicates a critic of that model element. Moving the mouse over the icon will pop up the critic headline.
Colored wavy line ( ). Used for critics specific to sub-components of graphical model elements. For example to underline attributes with a problem within a class.
Solid colored line ( ). Not seen in ordinary editing, but used when a to-do item is highlighted from the to-do pane (see Chapter 14, The To-Do Pane) by button 1 double click. The solid line is used to show all the model elements affected by the critic, for example all stimuli that are out of order.