How to remove a video transition in WL Movie Maker (2012)

I have completed a 9-minute movie project where I've added a few video transitions. Now I would like to remove one of them but am unable to figure out how. On the storyline transitions appear not as separate segments but as narrow triangles embedded inside the video clips to which they were applied. To right-click over such a triangle and "remove" looks the same as removing the entire video clip. Can anybody advise how to do this (or where I can find a detailed tutorial for the latest Movie Maker)? 

Thanks a lot in advance.