The manual (I think) has a mistake it shows as example:

I think it should be

For Each row As ListBoxRow In ListBox1.Rows (no?)

The other thing that happens is that the dot at row. do not show all the options

If you force the writting then it works, so do not show the option .RowColumnAt, for example, but if you write it then it seems to work.
Maybe a clarification will be welcome.

Used Xojo version used to create the project ?
Actual Xojo version ? (2019r3.1 ?)

Yes, the latest version 2019 r 3.1

For both (Project created with 2019r3.1 ?)

I may sent you (link) the project exemple if you want. It has only a listbox and a button.