This function changes the parent window of the specified child window.
A handle to the previous parent window indicates success. NULL indicates failure. To get extended error information, call GetLastError.
An application can use the SetParent function to set the parent window of a pop-up, overlapped, or child window. The new parent window and the child window must belong to the same application.
If the window identified by the hWndChild parameter is visible, the system performs the appropriate redrawing and repainting.
For compatibility reasons, SetParent does not modify the WS_CHILD or WS_POPUP window styles of the window whose parent is being changed. Therefore, it is not possible to change a window from parent to child or from child to parent.