virtual void Revoke( );
Remarks
Call this function before destroying any window that has been registered as a drop target through a call to Register to remove it from the list of drop targets. This function is called automatically from the OnDestroy handler for the window that was registered, so it is usually not necessary to call this function explicitly.
For more information, see RevokeDragDrop in the OLE 2 Programmer’s Reference, Volume 1.