afx_msg void OnNcPaint();
Called when the nonclient area needs to be painted.
An application can override this call and paint its own custom window frame. The clipping region is always rectangular, even if the shape of the frame is altered.
This message-handler member function calls the Default member function. Override this member function in your derived class to handle the WM_NCPAINT message.
CWnd::Default, WM_NCPAINT