Not always useful that a task is automatically completed when subtasks are completed
The auto completion of a task when all sub tasks are completed is useful but not in all circumstances.
For example when I manage a project I may have tasks that, in reality, are more like categories and they may contain sub-categories.
I would like to keep these always "not completed" unless I complete them manually as I may add new tasks to them later and therefore it would greatly help if they are always visible and not marked as completed with the line across (when not hiding completed tasks).
Adminsashika (Admin, Checkvist) commented
There is an option not to complete the parent task after its children have been completed (see the second option on the profile/settings page https://checkvist.com/auth/profile#appearance).
But this option works for all your lists.
Another workaround - put a dummy task under a 'permanent' parent, like 'Anything else?', make it italic to differ from the 'true' tasks. Thus you can combine both behaviours in a single list. (Disclaimer: we do it from time to time when we have a permanent task we shouldn't forget :)
Forgot to mention that this could be an option at individual list level.