I would like to see another option to be added - currently you can only complete a task. To move a task out of my outstanding task list I have to remove either the date, project, assignee or mark the task complete. I would like to be able to log a request that comes in and if for some reason the task is cancelled to mark it as so. I would suggest to have an X as well as Tick.
For example, current symbol and adding a second option to mark the task as cancelled: