The solution is to use Proxy Switcher for all the anonymous browsing needs. It can be used to avoid all sorts of limitations imposed by various sites. Be that a download site that limits amount of downloads. Or video site works only in a particular country - more often than not it gets defeated by the anonymous browsing features Proxy Switcher provides.
On top of that, if you used to manually change proxy settings Proxy Switcher provides a way to change them much faster and easier.