If you add a column/pre filter/etc, to an existing table or view you have to manually assign the rights. However 99% of the time you just want to give rights to whoever has the new sub object available. So in practice I go to the object, I filter only the roles that have available: yes. Then assign the rights. And go back to the new objects screen. In a big project you have to do this several times. It would be great if there was a task on the new objects screen: "Assign rights based on availability”. What this new task should do is give you the popup for the assign rights… task, but should be executed for all roles that have available: yes.
This task should be greyed out if no roles have the object as available (then you probably need to do something on main level first.