No, he's not. He means the triangular marker at the edge of the terraformer map, and when he clicked it the whole program crashed. This has happened to me a few times, although I'm not entirely sure how you fix the problem...
I also have some weird bug if I terrain a map, build a ride, and then use the contruction kit or something and water is enabled, it flickers all over the place. I don't know how to get rid of it, so I have to terrian up the ENTIRE map in terraformer to fix the problem.
That's because some of the features in the construction kit don't support terrain and water, so it deletes all the terrain data from the track file and leaves it with that flickering thing you described.