Calender view: Show completed re-occuring tasks
When a task is completed the task is shown in the calender view. No it's easy to trace what you have done on a day. But when a re-occuring task is completed, it is being rescheduled with the new date and not shown in the calender view anymore.
More simply add a check box to automatically create a new task after the recursion set, instead of changing the date.
This way all the tasks already performed remain visible and alterable