serious flaws in new calendar restore feature I: when we did not find the plan, and could not reconstruct it, we need to set it to null
serious flaws in new calendar restore feature II: when updating the event description, we need to make sure that we deal with an event in the right calendar
serious flaws in new calendar restore feature III: while we restore the preference, we do not want the onsharedpreferencechangelistener, that moves plans on its own to interfere