To do is buggy on Android also , Sharing is a compete fail. Shared Lists only functionality is cloning the a list to another user AT the time of Sharing. (might as well send a Screenshot to destination user!!!) If the destination user makes ANY changes to a task the Task disappears! Literally disappears from \the screen, if the destination user creates any NEW task the source user does not see the new task. To Do works great on Android if you have ONE user and NO collaboration whatsoever with ANYONE else. Hell I might as well use Notepad. Either MS totally broke Wunderlist Sharing or MS did NO testing in any way before deploying Shared Lists. My assumption is BOTH are true. I regret using To Do beyond words, UTTER waste of time.
Microsoft