BINARY capability not working correctly?

[Jouko Nikula]

Hello,

I have trouble with some attachments not working on Horde and
Roundcube. I made a ticket to Roundcube webmail and they tracked down
it to Dovecot not responding correctly to BINARY FETCH:

http://trac.roundcube.net/ticket/1490532

What is causing Dovecot to answer NIL? Is there an issue in Dovecot?

If I want to disable to BINARY capability in Dovecot I need to use
imap_capabilities. I found out that I could add capabilities with
syntax
imap_capabilities= +FOO
but it seems I can't use similar syntax (imap_capabilities= -FOO) to
remove capabilities? If I list all capabilities like:

imap_capabilities= IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID
ENABLE IDLE AUTH=PLAIN SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS
THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT
CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC
ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS SPECIAL-USE
MOVE QUOTA

I understood that this will result in listing all capabilities already
pre-login. Is this a problem?

Thanks,
Jouko Nikula