AAhh I love finding old blog posts that solve my problems!
I’ve been trying to turn this off in the new firefox as its now on by default, its a nightmare! If I middle click the tab bar to reopen a tab, it reopens then redirects to whatever was in my paste buffer. Useful feature if you’re used to it, pain otherwise. Also annoying on my netbook, where I sometimes middle click instead of double finger scrolling. Cheers.