A task's status depends on whether it has just been added, has been worked on or completed, or does not need to be worked on at all.
Changing status (Combo box on the top of the window) will show tasks of that status.
When Active status is chosen, selected and completed tasks are also shown together with the active.
The meaning of each status
Active - a task that has been added and will be worked on
Selected - a task that has been selected to be worked on in this or the next session
Inactive - a task that does not need to be worked on now, but may need to be reviewed at some point in the future
Deleted - a task that does not need to be worked on at all
Scheduled/Waiting - a task that does not need to be worked on now, but will be worked on/ reviewed at a specific future date
Completed - a task or a step that has been completed
Archived - a task that has been completed and archived; kept in the system for history/statistics