I have given the view permission to the admin portal to a specific group, and I also added the view permission to the AdminPortletInstance.
Now a member of this group can access the jboss admin interface, but when I go to a specific page's "page layout" interface, the portlet instance list below "Select content that will be added to the page:" is empty.
This list is apparently also rendered by some portlet, but I cannot find it and set permissions for it.
I'm having the same problem? Have you resolved it?