Firefox gives NS_ERROR_FAILURE error

Hi,

I recently updated to version 0.4.10, and now I'm getting a NS_ERROR_FAILURE error message in Firefox.
It seems to be a similar issue as issue #131. The error only happens when I load a (pie) chart in a hidden tab/div. I reverted back to 0.4.10RC5 and it worked again.

This is the full error that I see in Firebug:

```
NS_ERROR_FAILURE:
return $$.config.title_padding.top + $$.title.node().getBBox().height;
c3.js (line 4944)
```