IE 8 beta 1 : CSS2.1 bugs : z-index, stacking contexts and painting order

All modern graphical desktop browsers for windows including IE 8 beta 1 render positioned elements with z-index:auto as part of its nearest ancestor stacking context instead of its nearest ancestor with stacking context–like behaviour:

IE 8 beta 1 renders relatively positioned floats on the stacking level (painting layer) for floats instead of the appropriate stacking level for relatively positioned elements: