What is the purpose of adding Notes to action items if they can't be viewed?
There are few ways you can see Notes.
In the Home -> Organizer, in the Action Item can see the notes they enter and they can also see any Notes added by other people that are assigned to the Action Item.
Then, when you go to Administration -> Processes, and then go to the Initiated tab, you can filter on the name of the Process, and if a Note has been added, you will see it when you click on the Comments icon. And, even users that are not assigned to the Action Item can see the comments from here.
You can also see the Comments from Home -> Ideas, open the idea, and then go to the Initiated Processes tab.
Last but not least if you like to create a custom portlet with all Notes you can use the SQL below as a starting point that returns notes info for each process instance.
userId, csu.user_name userName,
bra.ai_status_code aiStatus, brs.id bsId,
brsar.id actionId, brs.step_id stepId,
bran.created_date noteCreateDate from
bpm_run_assignees bra left outer join
bpm_run_assignee_notes bran on
cmn_sec_users csu, bpm_run_steps brs,
bpm_run_processes brp where
bra.pk_id=brsar.id and csu.id=bra.user_id
and bra.ai_status_code not IN('CAL_OPEN')
and brs.step_id in (select step_id from
order by brs.id desc