UI Question

Hello Pharo Hackers, i am working my way through the wonderful pharocast videos and came across a video about UI building with polymorph. In this video a class UITheme ist used. Looking around in the system browser of Pharo 4.0 i can not find this class. Is this class renamed or is some other class used for this purpose now? I am working on a dvd database and a connection to the sqlite database is working with read and write access. I now need a GUI for my Application. I am thinking about documenting my steps. Maybe ot could help others finding there way. Yours sincerely, Fabian