steps to reproduce:
1. create a svg chart and define data
2. add a blank hyperlink interactivity to value series. that means multiple url value contain no url.
3. preview in html viewer.
you will see a mouse cursor on data points, but nothing happens when you click.

please note that png or other output formats can not reproduce.
fixed by checking if there are valid url redirections in defined action to enable hot spot.
verified in 2.5.2.v20100209