If you have previously recommended this thread, you should see a tick / check mark on the recommend button. Click the tick to undo the recommendation (the tick may appear to change to a cross as you do this.) If you added a comment with your recommendation, you will need to delete that from your facebook wall separately.
Having the bookmark thingy turned on means I can't seem to copy-paste words/sentences from individual posts. I'm finding I'm not using the Bookmark-Saved! option at all really, and so I'd like to turn it off but being a bit of a tech-idiot I can't seem to figure out how!