The framework calls this member function for each window in the Clipboard-viewer chain to notify it that a window is being removed from the chain.
Each CWnd object that receives an OnChangeCbChain call should use the SendMessage Windows function to send the WM_CHANGECBCHAIN message to the next window in the Clipboard-viewer chain (the handle returned by SetClipboardViewer). If hWndRemove is the next window in the chain, the window specified by hWndAfter becomes the next window, and Clipboard messages are passed on to it.
This member function is called by the framework to allow your application to handle a Windows message. The parameters passed to your function reflect the parameters received by the framework when the message was received. If you call the base-class implementation of this function, that implementation will use the parameters originally passed with the message and not the parameters you supply to the function.