I hear that a lot from folks who are confusing California statutes with Oregon statutes..
In Cali you HAVE to CC if you have a permit. In Oregon you can do either if you have a permit. If noone else posts the specific code I will get back here and list it for you.
To my knowledge there is no Penal Code requiring concealment UNLESS
that is a term of licensure specificly enumerated on the license as a restriction (which unfortunately is at the whim of the licensing authority)
(a)... A license to carry concealed a pistol, revolver, or other
firearm capable of being concealed upon the person.
(b) A license may include any reasonable restrictions or
conditions which the issuing authority deems warranted, including
restrictions as to the time, place, manner, and circumstances under
which the person may carry a pistol, revolver, or other firearm
capable of being concealed upon the person.
(c) Any restrictions imposed pursuant to subdivision (b) shall be
indicated on any license issued.