The second section in the Triggers tab is the Synchronisation palette. Creator can automatically have an action (or a series of actions) happen:
when a page or object appears (i.e. On Show trigger) or disappears (i.e. On Hide trigger) from the screen.
before a page or object appears (i.e. Pre-Show trigger) or disappears (i.e. Pre-Hide trigger) from the screen
when synchronised with the start or end of another event (i.e. the Synchronise triggers).
Synchronise to Animation Start Trigger
Synchronise to Animation End Trigger