problem with bill

[Philippe C. Martin]

Hi,

I am trying to get rid of a transaction or modify it. When I try to
delete I get "Generated from an Invoice, try un-posting the invoice".
(it is actually a bill: a refund to a customer)

I search for all invoices for this customer, some of them are described
as posted but when I try to un-post them, I only get the "post-them"
menu item.

I tried to have gnucash check the database, but no problem seems to be
found.

Where should I look ?

Thanks.

Philippe