I set my magic mouse middleclick at Tap Middle with BBT.
In previous versions of safari, middleclick works for open in new tab and close tab (when I click selected tab middleclick) but now close doesn't work.
What I can do with this?
I found solution for this
First you need download and install SIMBL.
After this download http://cloud.github.com/downloads/Kabal/MiddleClickClose/MiddleClickClose.bundle .zip and drop *.bundle to the folder:
you can found it at hard drive if you don't have it on user folder.
Next just relunch safari and it will works