Adblock Plus

What should i do if i mistakenly hide an element that is not an ad or a banner? How can i undo it? How can i unblock or remove the filter like you can do with ABP?

http://adblockplus.org/en/getting_start ... -positives
Same method, and there is a movie to show you how as well. Hidden elements are usually at the top of that blockable items list.

And in the future when you compose element hiding rules: Use the preview button, as well as the cancel button whenever appropriate.

You can find it in Preferences > My Element Hiding Rules.