there is many years now that I have troubles to understand why I have to subclass the ListBox to be able to do that because I do not do that in an old project.
Now, I have to wait because of a long download, I took time to search, find and open that old project (converted to Xojo 2015r1) and watch / search about what Ive done there.
As most of the time, the souvenir in memory is not eactly what the reality was.
I do not used Edit.Copy, but Edit.CopySpecial. That opens a window that let me set all sorts of tricks (delimiter, number of Rows, number of columns and whatever).
To be completely honest, that code, part of the project, is a bit confusing, but I really saw that the used ListBox is not a subclass and the Clipboard is filled aafter that nice window appears (think at LibreOffice speadsheet open text [csv ?] file).
a. Eureka ! (and I was not in my bath )
b. if you only have to implement special Copy / special Paste, and only that, you may do that without Subclassing the ListBox.