afx_msg void OnChildActivate();
If the CWnd object is a child window, OnChildActivate is called whenever the size or position of the window changes.
This message-handler member function calls the Default member function. Override this member function in your derived class to handle the WM_CHILDACTIVATE message.
CWnd::SetWindowPos, CWnd::OnClose, WM_CHILDACTIVATE, CWnd::Default