Cannot Render preserve-3d element below flat element

[pehrlich]

I believe this is to spec, from this example: http://www.w3schools.com/cssref/trycss3_transform-style_inuse.htm

However, it does cause an issue. Now that preserve-3d is relevant to both 3d transformations and the VR effect, it means that any WebGL content cannot be rendered in front of a transformed element.

With a wholly WebGL VR effect, an alpha 3d context could be given a unit preserve-3d as well, allowing it to appear in front of transformed dom elements. (Although granted, the manipulations for two matching VR Effect divs would be pretty difficult).