From Xojo Documentation
| This item was deprecated in version 2019r2.
Please use ListBox.AddRowAt as a replacement.
Creates a new row at row (zero-based), moving the existing rows below row down. For multicolumn ListBoxes, text is always assigned to column zero. The optional parameter indent specifies the amount of indentation of the row in hierarchical ListBoxes. The default is zero. It has no effect on non-hierarchical ListBoxes.
The following example inserts a row in the 'ListBox. The code is in a PushButton.