As I noted in Bug 877849, the hitCallback function might be better than setTimeout.

```javascript
_gaq.push(['_set', 'hitCallback', function() { window.location = href; }]);
_gaq.push(['_trackEvent', 'Tabzilla', 'click', href]);
```
instead of 
```javascript
_gaq.push(['_trackEvent', 'Tabzilla', 'click', href]);
setTimeout(function () { window.location = href; }, 500); 
```