   child window stuff
  when does standard window control paint?if you create a window, you call showwindow() and updatewindow() to show title ,client area,system menu etc....but for control like button ,dialog etc, when are these called?I am doing skin job on mfc. it need to replace window skin to other(custom pic). so I wanna know where does control draw their appearence(title ,cilent area etc...). I have the source.so just a little clue, I will work out.   
  solved,just overload Cbutton::DrawItem()   