|$showEmptyList = true|
Extended class to overcome issue when you have a list without any items to start with. This causes invalid XHTML because you have a UL without any LIs. This solves this problem by loading a filler li.
Set this property if you would like a hidden input field to be generated with $baseInputNameForSortableCollection as the input name. This is useful if you want to have an empty array passed via POST when a sortable has no rows, but is submitted. Otherwise without this set, nothing will be passed via POST. This is needed if you want to validate using CActiveForm that the sortable is required or some other type of validation.