[css3-regions] regions forming stacking contexts

   # Regions create a new stacking context. [...]
   # With regions, an element may be split across multiple regions and these
   # regions may overlap (for example if they are absolutely positioned).
   # So fragments of the same element can overlap each other.
   # Since each element has a single z-index, it would be required to find
   # another mechanism to decide in which order the fragments are rendered.
   # Since each region creates a new stacking context, it is clear that each
   # region is rendered separately and their rendering order follows the
   # regular CSS rendering model.

Fragments of the same element can overlap each other already due to inline
breaking, so this situation is not unique to regions.

Unless there's some compelling reason why they should be different, I think
I'd rather regions "followed the regular CSS rendering model" as you say at
the end... and did not create a new stacking context unless other CSS
properties on the region dictated it.

~fantasai

Received on Monday, 26 December 2011 23:58:47 UTC