7.1.X, 7.2.X, 7.3.X, Master
Steps to reproduce:
1. We create a vocabulary with a CAT1 category and a CAT2 subcategory.
2. We launch a Categories Navigation portlet with template Default
3. We configure the portlet to show us the vocabulary that we have generated in step1.
4. We can already see in the source code an empty list (ul) (it has no li children)
Actual: An empty list (ul) (it has no li children) present in source code, and it throws and accessibility error using TAW validator
Expected: Empty list (ul) (it has no li children) not present in source code