[horde] H5.2 & IMP 6.2.6 list user capability is "true" wrongly

[Steffen]

I have configured IMP as auth backend for Horde, but I have no admin user 
in the backend: "
  * admin: (array) Use this if you want to enable mailbox management for
  *   administrators via Horde's user administration interface. The mailbox
  *   management gets enabled if you let IMP handle the Horde authentication
  *   the 'application' authentication driver.  Your IMAP server needs to
  *   support mailbox management via IMAP commands.
  *
  *   Do not define this value if you do not want mailbox management [DEFAULT].
"

I don't want mailbox management from Horde and till H5.1 & IMP 6.1.7 to 
create new calendars and sharing anything worked without a list of users .

Now, in webmail 5.2.4 usernames cannot be validated in the share dialogue 
in services/shares/edit.php, because $auth->hasCapability('list') returns 
true .

problem 1)
After upgrade from IMP 6.1.7 to 6.2.6 I cannot create new calenders no 
longer. This can be avoided by setting
$conf['auth']['list_users'] = 'input';

This error is thrown: "Admin access not enabled."

If I change in ./imp/lib/Factory/AuthImap.php:

         $admin = $injector->getInstance('IMP_Factory_Imap')->create()->config->admin;
         if (!$admin) {
             //throw new IMP_Exception('Admin access not enabled.');
             $admin = array();		// TODO
         }

I get "Listing of users is nor supported."

problem 2)
sharing calendars, tasklists, notebooks and such I cannot set permission 
to other users, because the user cannot be validated, because of this 
snippet in edit.php:

         } elseif ($auth->hasCapability('list') && 
!$auth->exists($new_owner_backend)) {
             $notification->push(sprintf(_("The user \"%s\" does not 
exist."), $new_owner_backend), 'horde.error');

====

I patched Core/Auth/Application.php to return false always:


         if($capability == "list")	//TODO
         	return false;
         return in_array(strtolower($capability), $this->_appCapabilities);

Now H5.2 behaves as H5.1.

Did the upgrade from H5.1 to H5.2 introduced a new setting controlling 
this capability? I did not found something in Horde nor Imp config.

-- 
Steffen