Superposition doesn't stop, or that at least is what I understand. The uncertainty principle can be expressed in terms of increments of energy and increments of time: the farer I could be from where I am supposed to be, so to say (that is the energy increment) is inversely proportional to the time that can be measured (that is the time increment).

However, given that I'm no expert on the topic, I wish someone in a better position could elaborate on this idea.