Hi i have been having problems getting a lot of functionality working in many websites in Firefox where there is no problem in IE. A particularly problematic is site is Twitter where most of the functionality doesn't work (All dropdowns, number of characters remaining disappears, can't tweet etc). On investigation this is being caused by the prominently advertised Firefox add-on "Ad-Block Plus" which i have enabled. (When i disable it, everything works). When i check the list of blocked items on the Twitter page there are none. Therefore this add-on is causing severe problems. I appreciate Ad-Block plus is designed to block items, but when it is not blocking anything on a page it shouldn't block functionality. I also appreciate Mozilla do not make or support Ad-Block plus, but my point is that you are encouraging users to install an add-on that ruins website functionality. There are a couple of add-ons that have an exclamation mark and warnings they are unsafe, i would suggest Ad-Block plus now has some warnings on it? thanks Richard