Feedback 1
Feedback 2
Feedback 3
In the normal state the bordered feedback draws a border (a shadow of style ``raised'') around the button---the shadowed feedback displays nothing. In the excited state (when the button is pressed) the bordered feedback draws a shadow around the button of style ``lowered''---the shadowed feedback displays a plain border. When the button is released the buttons regain their normal appearance.
A feedback (Feedback.T) maintains a boolean state: ``on'' or ``off.''
The appearance of the feedback depends on this state.