This is an example of using 2 SWF's in the full screen popup, with the 2nd SWF being used for a small SWF close button. Both SWF's use 'window' for wmode, and the close button SWF is on top of the main full screen popup SWF. The close button SWF uses the FS Command in the popup to close the popup when the close button SWF is clicked.
This 'SWF over SWF' method was developed by Richard Eagle in April 2002, and it is useful for adding a close button to an existing SWF in a full screen popup where you don't have the .fla or .swi file, while still allowing you to use 'window' for wmode for faster/smoother animation.