The Parallel Citation tool is effectively an extension of the precedent tracker, its subtle difference is that it maps out subsequent cases which share at least two citations with your current case, even if your current case itself is not actually cited.

If the cases decided subsequent to your case do not cite it, look at those subsequent cases for an insight as to why, and determine what other cases you might need to refer to in your research.

The graph works the same way as the precedent tracker does, and show citations to every case.

For more information check out the help page on JADE.