I think it would be useful if it was possible to run/play an ActivationAnimation w/ a trigger. A usecase would example be that if you have one or multiple pages you toggle inside another page. This would let you run the AddingAnimation when ex. you toggle the screen away by the click of a button. I guess you could always recreate the animation with a WhileTrue as a workaround but since the properties for the AddingAnimations tends to be a little different , it would be timesaving and useful in these scenarios.