This option only applies

This option only applies to calendars that have themeSystem set to 'bootstrap'. A FontAwesome stylesheet must be loaded before you can use Bootstrap 4 theming or customize the icons. Getting started with FontAwesome.This option only applies to calendars that have themeSystem set to 'bootstrap'. A FontAwesome stylesheet must be loaded before you can use Bootstrap 4 theming or customize the icons. Getting started with FontAwesome.