Hello,
In previous versions I was able to do this:

$('a').live('click',function (e) {
        alert(e.button)
        return false
})

With that code I was able to do something on middle clicks and also to disable the default behaviour.

Now, with version 1.4.2 I can't do that any more.
Using the 'mouseup' event I can get middle clicks but I can't disable the default behaviour.
I have tried e.preventDefault() or binding both events: .live('click mouseup',etc) but nothing works.

Now, some people use to ask why I want to do this, I'm developing an application that has tabs and middle clicks should open tabs in the background or close tabs:
http://yuzem.blogspot.com/p/figuritas.html

Thanks in advance!