private void DoAddButton(Rect position, int controlID, IReorderableListAdaptor adaptor)
{
GUIStyle addButtonStyle = ReorderableListGUI.defaultAddButtonStyle;
if (adaptor.Count == 0) addButtonStyle = ReorderableListGUI.defaultAddButtonStyleIndependent;
if (GUI.Button(position, GUIContent.none, addButtonStyle)) {
// Append item to list.
GUIUtility.keyboardControl = 0;
AddItem(adaptor);
}
}