Treerow treerow = new Treerow();
Treecell nameTreecell = new Treecell();
Label nameLabel = new Label(baseCalendar.getName());
nameTreecell.appendChild(nameLabel);
treerow.appendChild(nameTreecell);
// append start date of the current work week
Treecell startDateTreecell = new Treecell();
Label startDateLabel = new Label("---");
CalendarData version = baseCalendar.getCalendarData(LocalDate