The central plus button looks like a main entry point for adding tasks or events in the mobile app, yet, one cannot create an unscheduled task with it. IMO, it should be possible to create both scheduled and unscheduled tasks using the only button, no matter if it's the task list or the calendar component that is active right now. Alternatively, if the plus button needs to depend on what component is active right now: tasks or calendar, it shouldn't be shown in the fixed bottom bar, but should instead be a part of that component, so that it's clear that it performs a contextual action only. I personally always press plus firstly, and only then remember that Inbox tasks cannot be created from there, which is frustrating.