The most useful Add-on ever. Rated 5 out of 5 stars
I use this Add-on to get notified about forum postings replies and updates to some portable apps.
When I right click on a folder you should show a new entry in the context menu that allows to edit the settings (Check Interval, Highlight color) for all entries in the folder.
I have organized my pages in folders and would NOT check some folders at work (manually adjust many entries) and the highlight color for two forums (yellow is not good to see, here I also would have to adjust many bookmarks manually).