A container is a collection of Components.
o-+ Component o-+ Container o-- ComboBox o-- GroupFrame o-- ListBox o-- TitleFrame
description from overloaded method of Component:
marks component to be updated on next validationcalled whenever the displaystate is changed, i.e. if the component was made invisible, or it's parent was removed from the rootpane etc.
A component that is displayed has not to be visible.