By default, containers create only the controls that initially appear to the user. Flex creates the container's other descendants if the user navigates to them. Containers with a single view, such as Box, Form, and Grid containers, create all of their descendants during the container's instantiation because these containers display all of their descendants immediately.

Containers with multiple views, called navigator containers, only create and display the descendants that are visible at any given time. These containers are the ViewStack, Accordion, and TabNavigator containers.

When navigator containers are created, they do not immediately create all of their descendants, but only those descendants that are initially visible. Flex defers the creation of descendants that are not initially visible until the user navigates to a view that contains them.

The result of this deferred creation is that an MXML application with navigator containers loads more quickly, but the user experiences brief pauses when he or she moves from one view to another when interacting with the application.

You can instruct each container to create their children or defer the creation of their children at application startup by using the container's creationPolicy property. This can improve the user experience after the application loads. For more information, see About the creationPolicy property.

You can also create individual components whose instantiation is deferred by using the createComponentsFromDescriptors() method. For more information, see Creating deferred components.