Greenhopper calculates scope of a version based on the issues that are related to a version.
This is very handy to visualize scope increase (or decrease) using the chart board.

What is missing is the concept of a baseline, so that you can compare the
scope against what was initially committed to.

When we are running a sprint we do 'in-flight replanning' meaning that we are moving
some stories back to the product backlog because other stories are taking more
time, or because stories are 'below the line'

At the end of the sprint, I'm getting questions like 'at the start of the sprint
we had initially 520hours committed, but the current graphs shows only 460 hours'

At that moment it would be very useful to be able to show:
This is the list of issues we took initally in the iteration, and these have been dropped
'in-flight', to be able to deliver the other priorities, or the way around,
'during this sprint following stories have been added to the iteration'