ListBox.DropIndicatorVisible

From Xojo Documentation

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

New in 2019r2

Supported for all project types and targets.

Determines whether or not the drop indicators appears. This property simply changes the appearance of the listbox. It does not prevent the new events from firing.