There shouldn't be any difference. How are you trying to access the data - Editor/Schema Browser/Both? Are you sure your using the same account and using the same connection type (eg. Normal/SysDBA/etc.)? Does running the query in SQL*Plus return the data using that same account?
I just created a read-only account on our local APPS db and it works in 12.10 here. I ran the following in the editor and it returned the rows correctly...
select * from apps.hr_locations;