Optional
spatialNavigation: SpatialNavigationFires when a component is hiding.
Fires when a component is showing.
Fires when the UI is fully configured and added to the DOM.
Fires when the UI controls are hiding.
Fires when the UI controls are showing.
Fires before the UI controls are hiding to check if they are allowed to hide.
Fires when the UI controls are released.
Fires when the seek timeline is scrubbed.
Encapsulates functionality to manage a UI instance. Used by the UIManager to manage multiple UI instances.