The process debugger runs parallel tracks simultaneously, and marks eligible steps in each track. All step navigation buttons are enabled, including their corresponding menus.

When a process has multiple parallel tracks that lead to an OR join, at least one transition must be taken. The tracks not taken are called dead paths, because they do not execute. The process debugger waits for all transitions, both live and dead paths, to arrive at an OR join step before that step can become an eligible step, and before the process can proceed to any step after the join step. A join step sometimes enters the waiting state before it appears that any transitions to it have been taken; this is due to the arrival of an incoming dead path transition.

For more information about dead paths, refer to How Incomplete Transitions Affect Join Steps and Gateways.