Before and After Property Sets in the Clip Editor
The Before and After Property Sets tabs allow the value of any Custom or System Properties to be set before or after a given container or nested clip. In the Clip Editor, the Property Sets Before and Property Sets After tabs appear in the lower panel whenever a container or nested clip is open in the Clip Editor lower panel.
For any container in the Clip, such as a Group, Transaction, or nested Clip, the Before and After Property Sets tabs allow you to set the value of any Custom or System Properties before and after play of that container. This allows you to control or change the behavior of the container, or receive output values from the container.