When you are gathering the end-user choice through a SMS List Records widget, the following runtime properties are available:
LineCount: Maximum number of rows that can be displayed in the widget, as defined in the Line Count property of the widget.
Read only. Integer type.
StartIndex: Indicates the index of the first row in the list to be displayed in the widget.
Read / Write. Integer type.
List: Allows you to manage the list displayed by the widget.
Read / Write. List type.
The Line Count and Start Index properties are very important for implementing the Previous and Next behaviors of a List Records.
About Runtime Properties