I have a ticket which is parent of other tickets and it has set fields.start and fields.finish. I understand both fields as they are for setting the planned range of time.
But the chart don't display the given start date in column "Start Date" correctly, but it seems to compute a new start date from "End Date" minus worked hours. That confuses us when reading the chart as plan.
BTW: on several places it's not clear in the chart what is just data of plan/schedule and what is data of the past reality. This should be clearly distinguished by the chart, maybe by colors. This is somehow related to #8786.