Problem with TCallBack from openGL demo project.

[jjaaxx44]

hey friends,
i am looking at some example projects from sdk. i came across some weird problem.
in opengl project (\S60CppExamples\OpenGLEx\SimpleCube) ConstructL of CSimpleCubeContainer lines

iPeriodic = CPeriodic::NewL( CActive::EPriorityIdle );
iPeriodic->Start( 100, 100,TCallBack( CSimpleCubeContainer:: DrawCallBack, this ) );

in DrawCallBack :
instance->iSimpleCube->AppCycle( instance->iFrame );

but when i add some other class and make object of it in AppInit of simplecube.cpp file, TCallBack does not call DrawCallBack...anybody know why is this???

thanx in advance.