Maybe i'm wrong, but as i understand, the order of elements in the Navigator panel should represent their order on screen (like layers in photoshop).
For some reason, it doesn't work for me:
Notice that the Div with the green arrow is on top of another Div, but in the design it's actually beneath it.
I checked the z-index of all items, and it doesn't seem that the problem is because of that.
I've been pulling all my hair off by now, and didn't get it to work.
Here is my public share link: LINK