It used to be (like a week ago) that removing an item from the active Sprint Backlog caused it to show up in the historical list of actions on the Burnup, and was shown as a drop in the top-line value on the date of the change.
Right now, an item removed from an active Sprint Backlog disappears from the list of items initially brought into the Sprint, and its points aren't counted in the initial points value (and so don't show up as a change in scope in their historical place on the chart).
