I have the trial version of MMF2 that came with "Going To War: Creating Computer War Games". The tutorial in the book instructs you to create a string and then set it so it will bounce off the edges of the play area.
I created the object and an event that tests if it is near the edge, as the book instructed. However, when I select "Movement" under the responses, all the possible movement types (stop, start, bounce, reverse, etc.) are grayed out.