View.copyColumn returns null

I am trying to create a new view (programmatically) that has categorised columns. Unfortunately, the “isCategorised” property of ViewColumn is read only.

To get around this, I am trying to copy another column that IS categorised, then adjust the attributes of the copied column accordingly.

This works the first time I call it, but when I try to create a second categorised column in the same view, the “copyColumn” method returns null.

This is strange because the documentation suggests that the method always returns a ViewColumn (or otherwise throws a NotesException).

has anyone seen this before?

Or is there another way to create a categorised view?