From Xojo Documentation

Property (As Boolean )
aListBox.AllowFocusRing = newBooleanValue
BooleanValue = aListBox.AllowFocusRing

New in 2019r2

Supported for all project types and targets.

If True, the control indicates when it has the focus by drawing a ring around its border. If False, the appearance of the control does not change when it has the focus.