GUIs lend themselves very well to an object abstraction. The discrete elements (dialogues, menus, controls, etc) are objects that often inherit behaviour from c

GUIs lend themselves very well to an object abstraction. The discrete elements (dialogues, menus, controls, etc) are objects that often inherit behaviour from classes of objects (i.e. A modal dialog is a generic dialog is a form is a ...). Events are messages between objects. We even see things like polymorphism eg. anything can get a "click on" message, but different objects behave differently when clicked.