In short: Not with the old API. In this recent newsgroup post, you can see a list of the things that could break an extension, and it's a lot. http://groups.g

In short: Not with the old API. In this recent newsgroup post, you can see a list of the things that could break an extension, and it's a lot. http://groups.google.com/group/mozilla.dev.planning/browse_thread/thread/dafd0bc59b587e27# http://groups.google.com/group/mozilla.dev.planning/browse_t... The work to solve that is mentioned in the thread.