How to configure IMAP mailbox in KMail where item To Trash has been greyed out

[Freek de Kruijf]

Hi,

I have two IMAP mailboxes in KMail to two different servers in where I can't 
delete messages from the INBOX folder. It is possible to copy messages from 
these mailboxes to folders in other IMAP mailboxes and also to another folder 
in the same IMAP mailbox.
The item "To Trash" in the Toolbar is greyed out for the INBOX folder in the 
two IMAP mailboxes.

I have other IMAP mailboxes on the same servers, these work OK.

I manage one server, running dovecot, but I do not have control over the other 
server.

How to analyze and solve this problem?

-- 

fr.gr.

Freek de Kruijf