Containers are rectangular regions where other components are contained. The components inside container are called children of container. These children can be controls or other containers also. Application container is the root container which contains all child controls and containers.
Flex provides two types of containers typically termed as:
1. Layout containers and
2. Navigation containers
Layout Containers includes containers like Panel, Form, HdividedBox etc. used for positioning child components while navigation containers like Accordion, TabNavigator and ViewStack are used for controlling the movement from one child container to the other.
See the image below containing two panels Panel1 and Panel 2 within the top Application container.
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