What is inheritance and permission hierarchy levels?

AceACL offers you the possibility to set the permissions to component/category and apply it to it's items (articles).

That is the same as applied in the Joomla 1.6/1.7 but with 2 important improvements/differences:

1. There is NO DENY WINS. So that means that you can override a deny set to component/category from it's item. In other words, the lower (deeper) level (Global=>Component=>Category=>Item) allways wins, assigned permissions beats inherited:
  1. Global – here is where you set the default allow/deny actions (permissions).
  2. Component – setting permissions for a component (menu, articles etc) overrides the Global permissions
  3. Category – setting permissions for a category overrides the Global and Component permissions.
  4. Item – setting permissions for an item (article) overrides all of the above.

2. There is NO GROUP INHERITANCE. AceACL uses groups just to categorize users and the name of the group does not matter in any way. Another important point is that if one group gives you access then you are in.