Preview/media switch places while zooming/panning

I am using iMovie in my classroom for all kinds of movie editing.

Since the launch of iMovie 2.0 we sometimes notice the 'preview window' and 'media window' switch places when zooming and panning photo's. This problem not always occurs and is hard to replicate, but I managed to make a little movie. In this movie I exaggerate the zooming and panning to replicate the problem. Is this a feature or a bug? I had it with iOS 6 and also in iOS 7.

https://www.youtube.com/watch?v=-jvCFl7x6P4

Thanks