SFC Draw Charts must be complete. That is they must conform to the rules, so you cannot draw illegal charts, for example have a transition that goes nowhere or jumps into or out of parallel steps.

SFC Draw renders the chart complete by:

        Deleting Steps and Transitions that do not connect back to the start.

        Connecting transitions that go nowhere to the the End Step.

        Putting a Transition connected to the End step after Steps that go nowhere.