[Haskell-cafe] hawiki Haskell SDL openGl example works strange

Hello, again, I tried to run the example from http://haskell.org/hawiki/HaskellOpenGl (the SDL version), but the scene is shown, only when I resize the window. I tried to insert the drawGLScreen before mainloop call, but it didn't worked. Do you some idea how to resolve this little problem? Thanks Matej 'Yin' Gagyi