Hi, so, his have a software, if you log in to another user, apps don't run, Along with this, the software also. therefore, o software, responsabilized to send system information, don't run. therefore there will be no information to be sent for screen. If you want a LCD 3.5" run in all users, you need dowload software in all users, or copy file in admin user and paste in second user.
If you didn't understand the writing, sorry, I'm Brazilian and I'm just training my English. good evening