Check your shortcuts. One of them will allow you to select the Service or Theme area. When using one screen the live screen is the main screen and covers the rest of the apps on the desktop. You should have a way to change your focus to OpenLP, then use the shortcut to make sure the Service or Theme is active....at this point the arrow keys should work...just make sure you have them enabled in settings....if you have trouble with the Left and Right arrow keys, try the Up and Down arrow keys.<br><br>Myself, and I am running Windows not a MAC, when I am using a PC with only one screen, I go into settings and change the screen to use 2/3 of the available screen. This way i can click on OpenLP when the live screen is displayed. I use the 2/3 size so the screen ratio is the same and things display almost like they should.