Where does this 'tooltip window' come from?

My friend and I are busy trying to create a small cardboard demo for a school project in Unity.

The moment we go into game mode and our mouse enters the game screen, a huge tooltip window enters the screen, the top left corner is the position of the mouse. I tried looking for onMouseEnter functions in scripts, but could not find anything.

The demoscene we downloaded: https://developers.google.com/cardboard/unity/download The screenshot :

I could not find anything, so I really need some help. If you need more information I'd be happy to give it.