When I change the start date of a task in the tree list on the left, the end date is automatically updated. It seems that the system keeps the same number of days between the two dates, but not always. However, if I change the start date in the task editor window (double-click on task bar on the right-hand side), the end date does not get updated by the system. This appears to be inconsistent and undesired behavior. How can I suppress the automatic update of the end date when I change the start date?