ListBox.HasVerticalScrollbar

From Xojo Documentation

Property (As Boolean )
aListBox.HasVerticalScrollbar = newBooleanValue
or
BooleanValue = aListBox.HasVerticalScrollbar

New in 2019r2

Supported for all project types and targets.

If True, adds a vertical scrollbar to the ListBox. The position of the thumb is indicated by ScrollPosition. The default is True.