gThumb is not developed by Manjaro. Report to the proper channel Issues · GNOME / gThumb · GitLab
Feature requests for Files should go to the proper developers too Issues · GNOME / Files · GitLab
Without providing system information and what extensions you have enabled, is almost impossible to connect any dots here.
Haven’t you already mentioned that in your first post here?
Check the Welcome and introduce yourself - 2022 - make yourself known to the community, no need to repeat credentials every time. 
By the way, did we really need those pointers in bold tho?