Hi, I'm using WinMe and vtk4.0. 1 I built the \vtk40\Examples\GUI\Win32\SampleMFC and SimpleCxx, they all can run. But why the SampleMFC cannt interact as the SimpleCxx ? And How to make the SimpleMFC support interaction. 2 I successfully built the source codes of VTK with VC6.0 and CMake. But how to trace into the VTK's source coed while debugging? colin