DesktopListBox.RowExpandableAt
From Xojo Documentation
Method
DesktopListBox.RowExpandableAt(row as Integer) As Boolean
New in 2021r3
Supported for all project types and targets.
New in 2021r3
Supported for all project types and targets.
For hierarchical ListBoxes, is used to get or set whether the row should be displayed as expandable.