code: public void showDateDetails(Node owner, LocalDate date) {
          maybeHidePopOvers();
          datePopOver = new DatePopOver(this, date);
          datePopOver.show(owner);
      }
docs: Creates a new {@link DatePopOver} and shows it attached to the given
  owner node.
  
  @param owner the owner node
  @param date the date for which to display more detail