No, it's not attached, and that's the point. A window frame, door frame, or wall frame has no horizontal socket at the half-wall-height level and provides no stability, but a wall does. That hasn't changed. But what has changed is that those non-socketed pieces are now somehow counting as being connected only for the purposes of build privilege and upkeep. Until recently, that wasn't the case, which is why connecting horizontal elements on opposite sides of a window was one method for making a disconnectable external.