Hey, I've been tryna get this feature to function for the past half hour. The button just doesn't seem to work at all. I've left clicked, right clicked, double clicked, middle clicked, tried some button combos but the 'Import custom image' button doesn't do anything at all. Is the feature broken in the current version?

EDIT: Upon further research it seems the feature is completely broken on Firefox. It works on Edge and Chrome but not Firefox.