Class not being appended (not working)

Hi and thanks for the plugin. I am having issues getting it to work though. I see the CSS is being added to the page with the rule for .hide_this_item, but any item I put a checkmark on, with the expected result of the class “hide_this_item” being added to the actual element, never gets added. So it’s not working over here. Anything I should check out or change to fix it?