I have an interactive animation that shows step by step how a process takes place. I have some new objects appear as the user proceeds through the animation. I also have a button that takes them back 20 frames and replays the last step so they can review what happened. The problem is that the things that appear on the timeline on frame 50, do not go away if I go back to frame 30. They are still on the stage. I have checked the timeline and nothing is there. what is going on.