Test case:
Blue div has 400px width, dynamic height, and position: relative.
Inside blue div there are 3 other div with height: 40px (and has some bottom margin..)
the height of the blue div expands with the green divs inside..
Yellow div has position absolute (and positioned in the top left corner of the blue div)
it's height set to 100%
the height of the yellow div now equals with the height of the blue div
Red div is inserted into the yellow div, and it's height set to 100%
Problem:
The height of the red div should equals to the height of the blue (and yellow) div.
It works right with Opera 9.2, Firefox 2, Camino 1.0.4 and Internet Explorer 7.

Workaround:
If you set position absolute to the red div, it's height will expands along with the blue div.

Result:
PASS: redHeight == yellowHeight
PASS: redHeight == blueHeight