I seem to have found a bug in the Group Permissions configuration.
I can only create one Level on top of the four defaults. I create a level (eg Public1), I assign some permissions to it, it seems to work. Then I create another level (eg Public2), and lo and behold! Public1 has disappeared from the dropdown lists of levels!
This must be a bug.
In addition, I would like to say that I find the way the permissions work incredibly confusing. The reason I want to create different "public" levels is that if I assign "basic" to my anonymous users, then it actually assigns ALL the basic permissions to them, including those that belong to features which I've not turned on!
In addition, the list of permissions for the group is unbelievably long and tedious.
Moreover, there is no way of easily viewing the permissions assigned to a Level.
IMHO, what is needed is this:
1) groups inherit permissions from one or more levels; the groups permissions only show the levels, not individual permissions
2) a levels administration screen where it is possible to see at a glance what permissions are atatched to a level
All the best, Joel