ListBox.ScrollBarHorizontal

From Xojo Documentation

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

Supported for all project types and targets.

If True, adds a horizontal scroll bar to the ListBox.

Notes

The horizontal scrollbar only appears if the sum of the widths of the columns exceeds the width of the ListBox itself. If the widths of the columns is less than (or matches) the width of the ListBox, then no horizontal scrollbar appears.

The position of the thumb is indicated by ScrollPositionX. It is used to scroll the ListBox horizontally without a separate Scrollbar control.