Problems with subscriptions & Thunderbird on 2.5.7

Robert Mueller robm at
Thu Apr 14 21:17:23 EDT 2016

FYI a user of ours encountered this recently and we came to the
conclusion it's a Thunderbird bug. An edited conversion I had with Bron
is below.

Checking the Thunderbird bugzilla, I see multiple reports of this. In
particular a bug that was supposedly fixed in 2010 seems to have
recently re-appeared for some people.

See comments near the bottom of that bug. Someone has opened a new bug.

I see an old bug similarly related to this.

There's this comment near the bottom:

Workaround was fortunatly found accidentally : Double click of IMAP
When IMAP folder was double clicked at folder pane, expand button
automatically appeared and subfolder was automatically shown when
subfolder exists.

Can you check if that works for you?


It appears LSUB and LIST (SUBSCRIBED) are only returning \HasChildren if
there's a subscribed child mailbox, not if the actual mailbox has
children. That seems wrong...

Example in a users mailbox.

. list INBOX.x.y.2015 *
* LIST (\HasChildren) "." INBOX.x.y.2015
... many more sub-folders ...

. lsub INBOX.x.y.2015 *
* LSUB () "." INBOX.x.y.2015
. OK Completed (0.010 secs 2 calls)

. list (subscribed) INBOX.x.y.2015 *
* LIST (\Subscribed) "." INBOX.x.y.2015
. OK Completed (0.010 secs 2 calls)

My reading of those is that they're correct.  HasChildren actually only
needs to be calculated in two cases:

1) it's been explicitly asked for with a RETURN option in LIST-EXTENDED

2) the expression matches a non-existent intermediate folder, but not
its existent children.

Otherwise it's nice to do, but not required.

In particular, both LSUB and RETURN SUBSCRIBED only iterate the
subscriptions database - so they don't know about children.  We don't
calculate them unless explicitly requested.

I really do think it's a Thunderbird bug.

. list INBOX.x.y.2015 * return (children)
* LIST (\HasChildren) "." INBOX.x.y.2015

. list (subscribed) INBOX.x.y.2015 * return (children)
* LIST (\Subscribed \HasChildren) "." INBOX.x.y.2015

Yeah, I think you might be right, the lack of both \HasChildren or
\HasNoChildren shouldn't imply anything.

On Wed, 13 Apr 2016, at 01:05, Giles Malet via Cyrus-devel wrote:
> Before I head off to read RFCs, and try to understand what Cyrus is doing
> and Thunderbird, and what is going wrong, I just wanted to ask if anyone
> already knows the answers. Specifically, using LIST-EXTENDED, should a
> mail client be able to determine which folders are subscribed to, and if
> so why is Cyrus apparently not returning that information? Conceivably TB
> is doing it wrong though. And if TB is trying to set a \Subscribed flag
> on a folder, should that be updating Cyrus's list of subscriptions?
> Anyhow, I'll see if I can get some traces of what's going on, and see if
> that's what should be going on.
> Thanks,
> g

Rob Mueller
robm at

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