Note that the js is not minified so it is readable. See window.js for the full source code.
This illustrates the
headerPosition config of Panels, and also relative z-index management.
The third Window owns two floating Windows who's z-indices are managed relative to its z-index. When that Window is occluded by another Window, and you click to bring it to the front, both its dependent Windows move to the front too.
This also illustrates constraining Windows.