We don't use sort_delimiter in IMP 6.2 anymore.

It shouldn't.  i.e. even if the delimiter is '/', these should still 
be sorted correctly:

Foo
Foo/bar
Foo/bar/baz
Foo2

since '/' > any character/number in sorting.

It's not needed here because we can guarantee that all mailboxes will 
contain the same delimiter (since we don't allow special mailboxes to 
live outside the personal namespace).

I thought the sort_delimiter is needed for the correct hierarchical 
sort order even in the same namespace. As the default delimiter is '.' 
and my server uses '/', that would mess it up.

Though I manually changed the default delimiter to '/' in the 
Imap_Client source code to test the effects and the result still 
looked ok to me.

I tried to look at Imap_Client/test/Horde/Imap/Client/SortTest.php but
couldn't find an obvious example/test for the hierarchical sort.

Can you give a short example how this is intended to be used?

Perhaps we can work out a more verbose 'sort_delimiter' phpdoc text
that explains what it is actually doing.

This was intentional.  Since special mailboxes are restricted to the 
personal namespace, they will all share a delimiter so there should be 
no reason to have to manually define one.

Hi,

as mentioned on the dev mailinglist, 
imp/lib/Prefs/Special/SpecialMboxes.php::_getSpecialUse()
does not set the 'sort_delimiter'.

This is just a tracking bug so the issue won't get lost.

Thomas