Sorting Menu Items in Event Temple's Menu Item Settings involves a specific approach, as they initially appear greyed out and will show a tip to edit the Sub Menu. This is a result of the "Sub Menu = All" filter at the top of the Menu Items section.
Change the filter from "Sub Menu = All" to a specific Sub Menu.
Once a Sub Menu is selected, you can then drag and drop Menu Items to rearrange and sort them according to your preference.