It appears that the fill="none"
attribute on the polygon is what is suppressing the link.
If you change that to fill="rgba(0,0,0,0.0)"
(fully transparent black) the link works fine.
Here is a jsfiddle: http://jsfiddle.net/FE9LD/
And here is a jsfiddle with some css to add in the highlight effect (may need latest chrome): http://jsfiddle.net/FE9LD/1/