According to https://answers.atlassian.com/questions/6569/how-do-you-burndown-story-points-in-greenhopper-on-a-daily-basis, Rapid board burn down is determined by the rightmost column on the rapid board, this should be change to be a configurable column specified by the user.

The reason for this is that right most columns might include QA/testing activities, that do not effectively represent development burn down,
resulting in skewed burn down charts.