[css3-2d-transforms] Transformed object acts as containing block for fixed positioned descendants

In the introduction, it is said that:

   # Any value other than 'none' for the transform results in the creation of both 
   # a stacking context and a containing block. The object acts as a containing block 
   # for fixed positioned descendants.

I think we did agree earlier that this kind of normative statement should not be just intro material. 
But I was more curious as to the intended meaning of the latter statement ? First the spec says
the transform creates a stacking context and containing block. What's the extra bit about fixed positioned
descendants for ?

Received on Tuesday, 12 October 2010 22:18:55 UTC