Parallel
Similar to the Sequence task, the Parallel task will run each child task until a child task returns failure. The difference is that the parallel task will run all of its children tasks simultaneously versus running each task one at a time. Like the Sequence task, the Parallel task will return success once all of its children tasks have return success. If one tasks returns failure the Parallel task will end all of the child tasks and return failure.
The Return Status task returned a success status while the two Idle tasks are returning a running status. The Parallel task will continue to run until all tasks have completed with a success status or a single task returns failure.
In this example the Return Status task returned a failure status. Because a child task returned failure the Parallel task will stop all of its children and return failure.
The middle Return Status task returned success but the right Return Status returned failure. It only takes a single task to return failure and stop all of the child tasks.