I am running version 4.02
It only happens when I use categories that I have created. The categories that are pre-defined work nicely, as to sub-categories under them. I cannot get "Condo Fees | Unit 1" to work, but "Dues | Unit 1 fee" works (as "Dues" was pre-defined in NCH)
I just tried adding the categories under the Manage item rather than Categories icon and it works nicely. Problem solved.