Crossed out + Grey text for completed tasks to show (better if have filters on due dates, such as completed tasks (within 1 wk/2wk, etc.) [seen on other to-do list app and wish to see that feature as well on Morgen, sometimes wish to have that sense of achievement/ get tracked on my tasks (e.g. see what has to completed on weekends)]. Beneficial especially for sub-tasks to actually track the progress.