>Can not rely on its value? What the hell does this mean? The value of a form's HWND property can change during the life of the form?

No, hWnds are static once assigned to a window (at least nothing I can find in the Platform SDK contradicts this). What I think it means is that just because a particular form has a given hWnd does not mean it will be the same (in fact, it is unlikely that it will be the same) when you instantiate it subsequent times.