Limitation of Limited User in NAV 2013 R2

navuser1

Dear all,

I'm enthusiastic to know about the functionality/Restriction of a Limited User in NAV 2013 R2 (IN).
I have created a Limited User in my Database and assigned him 'SUPER' Role.

Observation :
Now user can able to create only Header Part of a new Purchase Order but he does not have the write/insert permission to create the Line Part.

Question
1. How does the NAV system restrict the above noted Workflow ?
2. Even User can not able to add/insert a dimension in a Purchase Order/Sales Order where the table 'Dimension Set Tree Node' is a "Limited User Included Tables"
3. How to define write permission on 3 table objects.

Waiting for your reply.
Thank you.