Thanks Colin,
The writing area behaves as you explain, the problem I had was in an earlier version (where I would get one or two lines of text visible).

For the second problem it seems to me that the way our imap server is set up (with subfolders) isn't ideal for claws-mail - if I understood correctly I can only turn off scanning for new mail for all or none (the way it's structured here is an INBOX where new mail arrives, and all other folders are subfolders of this one. I would like the scanning, but only for INBOX.. not its subfolders). I would have set up the imap server differently if it was up to me, I'll check if it's possible and if so talk to the sysadmin.