Ahh right, sorry I pasted that in haste. So in FRED CMP you can add RTE Configs. Since you are most likely using the FRED TinyMCE5 extra you can customise the richtext editor by adding your own configs.
Here is a config that we created for our FRED installations: https://gist.github.com/NatemcM/21c29df5a9154ef3e34c98ed22594d13. Simply copy and paste that code into a new RTEConfig set and name it TinyMCE. This will automatically be assigned to any element that has the following code: