Error fetching content

When trying out different selections of displayed results by clicking buttons on the left one very quickly gets this error (also see screenshot)

> Error fetching content. Perhaps web server has gone down.



The web server has not gone down ... I think what happened is that the selection of results do display is empty (you can trigger this error by deselecting both machines "cheetah" and "racoon" here: http://mdboom.github.io/astropy-benchmark/

Is it possible to improve the error message ... I think simply not popping up the error window in this case would be OK.