I have built a few browser extensions that live in GMail. Since they are larger extensions, they incorporate jQuery 1.6.x.
I am using jQuery as a content script which means it is injected into GMail then my scripts reference jQuery as they are loaded afterwards.
I have found that when other extensions are installed alongside of my extensions and they incorporate earlier versions of jQuery the earlier versions are loaded first and my 1.6.x is ignored. The functionality I have that depends on 1.6.x no longer works, and that's a dealbreaker.
I'm trying to come up with an elegant solution for this. My first instinct is to namespace my version of jQuery, but loading jQuery twice seams clunky. Possibly testing for jQuery and then doing a diff, but that seems tedious.