Can't copy text

I am using a form with some (simple) editable text fields, fieldA and fieldB.

One user (who upgraded to 6.5.2 recently) can’t copy the content from fieldA in edit mode using his client, although he has author rights and he can edit all items of the document. The menu option Copy is greyed out. Pasting still works.

All other users (using 5.0.x) working fine.

Controlled sections are not involved.

There is no $KeepPrivate field in the document.

Neither fieldA nor fieldB have an event.

How can I help him?

Subject: Can’t copy text

Does the form have a property set to prevent copying?

Subject: RE: Can’t copy text

No, I didn’t prevent copying.

Actually the database is somewhat more complex. I use a computed subform which contains the two fields fieldA and fieldB.