separateSelected method
Implementation
List<MultiSelectItem<T>> separateSelected(List<MultiSelectItem<T>> list) {
List<MultiSelectItem<T>> _selectedItems = [];
List<MultiSelectItem<T>> _nonSelectedItems = [];
_nonSelectedItems.addAll(list.where((element) => !element.selected));
_nonSelectedItems.sort((a, b) => a.label.compareTo(b.label));
_selectedItems.addAll(list.where((element) => element.selected));
_selectedItems.sort((a, b) => a.label.compareTo(b.label));
return [..._selectedItems, ..._nonSelectedItems];
}