z-indexvalue to positioned elements
So, what to conclude?
Community rocks. Without the link on high-profile web site like WaSP, I would still think that IE6 is right and Mozilla, Safari, Opera and others are wrong.
I managed to miss the fact that non-auto z-index does not create stacking context even after several readings. I probably needed a vacation. :) Many thanks to Dave Hyatt for taking the time to write the correction.
Much of my original conclusion was based on the miss-interpretation of the spec, so I simply deleted it.
I hope that these tests will help anyone dealing with complicated positioned content, where several blocks overlap each other.
Added note (Mar 18, 2008): With the introduction of IE8, we are finally closing in on ideal deployment solution. IE8 beta 1 passed all these tests with ease, thanks to its new standard-compliant rendering engine. We may have to deal with IE6/7 for quite some time, but we do see the light at the end of the tunnel.
If I'm wrong about anything said on these pages, please let me know.