It seems that ever since Windows Vista that VHD booting is supported natively, but in Windows 8, it seems when an item named in the BCD storage starting with [VHD] (including the square brackets), the icon is different as well: inside the “window” icon, the letters VHD are inside.

 

That concludes that Microsoft wants to go more to virtual workspaces. I did not find it on Google, so I’ll just went up posting it here as a reference.