OK. So when I am thinking and saying things like containers are
normally blind to their floated children, except for some IE
family containers (which auto grow height for them), I will be
adding that there is an official way to cause parents to see
their floated children, namely to trigger a BFC. An author can
always specify a height: but this "covering of the children" is
mere forcing the blind parent to provide something, it shows no
inner awareness (as it were) of the floated children. However, an
author giving the container a BFC gives the parent a more inner
intelligence, an awareness that can fend for itself, in effect,
it covers its floated children all by itself once the author has
triggered some genes in it...
Just thinking aloud...
That kind of thing, but don't forget that it's descendents, not just
children. As soon as a container is a BFC it wraps up any floats that
originate anywhere in the tree of nested containers inside it.
Furthermore it gets out of the way itself of any nearby floats from
other BFCs that might otherwise encroach over its borders.
Looking up the tree, every box has a "containing block" somewhere above
it, and a "block formatting context", which may be the same block as the
containing block but is often one much higher up the tree.
