Well I'm running Mac ROM 5.0 with ma5 firmware with ma5 stock kernel and it has the transparent multi window.....
http://i1093.photobucket.com/albums/i421/mrpnut3/Screenshot_2013-02-01-09-44-03_zps025d79d8.png
Sent from my SPH-L900 using xda app-developers app
You're running an LJC ROM with MA5 modem.
Sent from my SPH-L900 using xda premium