Pantaste-Window-Manager is a project mainly written in ActionScript, it's free.
A Flex 4 port of the Pantaste library
h1. Pantaste Library
Port to Flex 4 of the "Pantaste Library originally hosted on googlecode":http://code.google.com/p/pantaste/.
"View Example of Flex 3 Version":http://blog.comtaste.com/2009/06/example_of_implementation_of_t_1.html