Cannot put the first child on root

[quantica-william]

Hi there, first, sorry about the very bad english.

What I found is:

With you basic example, when I try to move the first child element (1. some sub-item content) to the root, he blocks me.
PS.: It only happens when I have two or more children, when it alone, work's perfectly.

To do that, I have 2 options:
1 - Put the first element into other position (like change the first by the second) and then move it to root
2 - Move all to root.

Well, as i cannot be so much clear, I recorded a video to "explain" what happened.

Youtube link: http://www.youtube.com/watch?v=XaGRaqR2j3E&feature=youtu.be

(It's a non listed video)