This topic is included for completeness. For more detail see the source code located in the VC\atlmfc\src\mfc folder of your Visual Studio installation.
virtual void OnBeforeChangeParent(
CWnd* pWndNewParent,
BOOL bDelay = FALSE
);
Parameters
[in] pWndNewParent
[in] bDelay
Requirements
Header: afxdockablepane.h