In the Symbian platform UI Control Framework, all UI elements (with a few exceptions) are controls. A control is a rectangular area of the screen that may respond to user input events. Buttons, menus, text input boxes and application views displaying application-specific data are all examples of controls.
All controls are implemented by deriving from the CCoeControl class.
Concrete implementations of controls are provided by a user interface library,
or by the application programmer. The control framework itself provides no
concrete controls.