User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.0.1) Gecko/2008070206 Firefox/3.0.1 Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.0.1) Gecko/2008070206 Firefox/3.0.1 Everything that is an extension of Firefox is in the add-ons panel. And there is the possibility to uninstall them. Search Engines are not in the Add-ons panel. Going to the Search Engine Field and then clicking the Search Icon->Manage Search Engines should lead to a tab Search Engines in the add-ons panel Reproducible: Always Steps to Reproduce: 1. Chose Tools->Add-ons 2. There is no tab for Search Engines 3. you have to close Add-ons and go to the search bar