if the change happens with every user role, i have no solution for you, but at the case is only for admin role, i think you maybe have taken diferent Skins for the administration than the portal one so, verify that in Admin -> Site Settings ->Appereance.
Look on the Skin lists from admin and portals, it should be the same if you want no diference. I don't know if is it a solution, but is the only similar i've seen.