Gisele,
Thanks for bringing this up. I think I have a fix and it will allow you to use the text filters with the icon text.
This fix will be in the Fordson 1.4.8 release later this week it will be in the repository.
I do believe me making this change will allow it to use text filters:
https://github.com/dbnschools/moodle-theme_fordson/commit/ba27f560ed69006c6390e14e920c94a6515fff43