Please consider implementing this with the Cancel/Abandon Canny feature request below. Cance/Abandon/Complete should all available as batch operations from the My Taks /Supervise Tasks screen.

Yes this is important. Large numbers of historic open tasks can build up which then need to be cleared.

Also, being able to hold down shift to batch select all the tasks between two separate tasks would be useful when trying to complete large batches of tasks in one go. Especially when clearing historic backlogs.

As mentioned elsewhere, being able to open a task from Supervise tasks before completing or reallocating would be useful.