... and this video, via the Clutter.org blog from Alex Larsson who wrote GIO and is now fooling around with windows and transparency extensions for GTK that work with Clutter/Moblin. Basically, he's showing a GTK editable window/dialog that then becomes partially transparent and pivots over on its side under 'gravity,' as if you pulled the thumbtack holding up its upper right corner.
I almost sprayed coffee at the checkbox marked 'Eat This MacSlow' ...