[horde] MIMP twice login

[Umut Arus]

Hi,

I have installed Horde Groupware Webmail Edition 1.0.1 with MIMP 
enabled. I had configured  horde/config/conf.php as shown 
http://wiki.horde.org/MIMPHowTo. Although IMP runs fine, MIMP login 
screen displays after IMP login screen. Before Horde authentication then 
MIMP authentication to login MIMP.

$conf['auth']['driver'] = 'composite';
$conf['auth']['params']['drivers'] = array(
    'imp' => array('driver' => 'application',
                   'params' => array('app' => 'imp')),
    'mimp' => array('driver' => 'application',
                    'params' => array('app' => 'mimp')));
$conf['auth']['params']['loginscreen_switch'] = '_horde_select_loginscreen';
if (!function_exists('_horde_select_loginscreen')) {
    function _horde_select_loginscreen()
    {
        require_once 'Horde/Browser.php';
        $browser = new Browser();
        if ($browser->isMobile()) {
            return 'mimp';
        }
        return 'imp';
    }
}

Why does MIMP ask twice login screen to MIMP?

Regards,