For projects with many parent/child/sub-child tasks, the current critical path analysis function does not provide a detailed enough analysis to determine which one(s) of the child tasks are driving the schedule end date.  The CP tool identified the highest-level parent task -  you are left to guess at which one of the sub-tasks (or sub-subtasks) is the task on the CP.  We have had to do in-depth CP analysis by using Project Transit to export a copy of the schedule into MS Project, and then identifying  the actual tasks on the CP. 

 Would this be the CP tool that is present in the Task -> Outline View? Both that tool and the one that is present in the Gantt Chart should give you red highlights of every single task, regardless of whether it is a parent, child, or 'grandchild' task, that is the critical path and driving the end date. Let me know if it is showing differently for you.

Yes, that is the CP tool I'm referring to.  Yes, I expected it to highlight every single task that was on the CP, whether parent, child, grand-child, great-grandchild, etc.  But it seems to stop at a certain level of decomposition.  That is, if you have a great-great-great grandchild, it isn't flagging as red/on the CP.

I looked at a CP in a test project I just created; it has six levels and from the top level parent task to the last task, all are highlighted. If you are seeing different behavior, I can go ahead and create a Support case for you; we can also double check with a screen shot I have if we are talking about the same behavior.