The SEGA Saturn theme splits items into pages with a maximum of 40 items per page. You can navigate through the pages using the and triggers.
Pressing on the leftmost page will take you to the first item on the page
Pressing on the rightmost page will take you to the last item on the page
If your triggers do not work, you can use SELECT + instead.
Pressing SELECT in the SEGA Saturn theme will bring up the DS Classic Menu by default. However, in the TWiLight Menu++ settings, you can change it to launch the SELECT Menu, a miniature menu embedded inside the theme itself. Here are the menu options for the SELECT Menu.