I've run into an issue when using the filter (show button) on m.toodledo.com.
When in a folder, selecting Show, and choosing to have subtasks nested hides all tasks that don't have a subtask. If a primary task has a subtask, it nests the subtasks accordingly, showing only the primary task. However, if a primary task doesn't have a subtask, it hides those as well.
I realize this is beta, so I just wanted to bring it up and see if this behavior is intended or perhaps a glitch?