I created new application using Top Navigation Menu template (Apex 5.1 on apex.oracle.com).
The navigation menu looks as follows:

Now I am trying to change the template of this menu, but no changes are being reflected. The following steps are what I followed:
- Shared Components -> Templates
- Navigation Menu -> Top Navigation menu -> Edit Component
- Name -> Template Class : change the class

No matter what template class I am using, the top navigation menu is still looking the same. For example I try to 'Vertical Image List' template class, but nothing looks different.
Am I missing something or doing something wrong here?