Window with user controls

User Control ===> added to the container (in order to be instantiated and displayed) ====> and where the container on it? [1: or user control ===> how to instantiate and show up? ===> added to the vessel ==> This is the cycle of death (paradox principle); 2 window (top window must be dependent, because the window can be instantiated and displayed independently, without relying on any other interface) ]