I don't know if this is the intended behavior, but I find it unnerving to only see uncompleted subtasks inside a checklist/project. It makes me wonder: did I finish those other subtasks, or did I never enter them in the first place?
Some of them do stay visible, but I can't tell if there's anything different about them. Maybe I marked those in the app instead of the web interface?
In the web interface, the completed subtasks stay visible, which give me more confidence that I really did what I needed to do.=