I am a Linux and FireFox user. For some reason, if you middle click a tab in FireFox, it loads some odd page from your history. Actually, what I think it is doing is loading whatever you have in your clipboard, and then going to that. Not sure, but anyway I found how to change that.
If you type about:config in the URL field, and then in the Filter field type ‘middlemouse.contentLoadURL’. Double click this Preference and then type in ‘false’. Now, if you middle click a tab, it will close. 😀
