NPE with ListModelList (with null item) and Selectbox

Using a selectbox with ListModelList, and having the first item on the list a null object, when users select this 1st element, NPE happens.

public boolean isSelected(Object obj) {
return !isSelectionEmpty() && (_selection.size() == 1 ? _selection.iterator().next().equals(obj) : _selection.contains(obj));
}

The problem is _selection.iterator().next() -> here it's a null object, can't call equals(obj) on it.