user32: SetWindowPos() should check the final window position in screen coords before adding SWP_NOMOVE.

user32: SetParent() should use ShowWindow() to make a reparented window visible and move a window to new position.

ddraw: The texture interface shares its refcount with the surface interface version used to create the surface.

This probably implies that on native the texture interface is part of a
separate object that's aggregated by the surface.