| Interface | Description | 
|---|---|
| Image | 
 An Image is a graphical element that can be displayed on a  
Device. | 
| MouseListener | 
 A widget has to implement this interface to be able to receive user mouse events. 
 | 
| Class | Description | 
|---|---|
| Composite | 
 A composite is a widget that can contain other  
Widget instances, following the composite pattern. | 
| Device | 
 A device represents the physical look of a device. 
 | 
| EventQueue | 
 The events queue is a mechanism to store some events in a linked list. 
 | 
| FrontPanel | 
 This is the super class of the front panel engines. 
 | 
| Widget | 
 Widget is the superclass of all the user interface objects. 
 | 
| Enum | Description | 
|---|---|
| MouseListener.MouseButton | 
 Some mouse events hold a mouse button. 
 | 
| Annotation Type | Description | 
|---|---|
| Widget.WidgetAttribute | 
 This interface describes only one attribute of the widget description. 
 | 
| Widget.WidgetDescription | 
 This interface allows a subclass of  
Widget to describe itself. |