Embedding HWND into external process using SetParent

HWND myWindow; //Handle to my application window
HWND externalWindow; //Handle to external application window

SetParent(myWindow,externalWindow);

//Remove WS_POPUP style and add WS_CHILD style
DWORD style = GetWindowLong(myWindow,GWL_STYLE);
style = style & ~(WS_POPUP);
style = style | WS_CHILD;
SetWindowLong(myWindow,GWL_STYLE,style);