diff --git a/plugins/libkolab/lib/kolab_storage.php b/plugins/libkolab/lib/kolab_storage.php
index 43f9c720..62b7796a 100644
--- a/plugins/libkolab/lib/kolab_storage.php
+++ b/plugins/libkolab/lib/kolab_storage.php
@@ -72,11 +72,11 @@ class kolab_storage
      */
     public static function get_folders($type)
     {
-        $folders = array();
+        $folders = $folderdata = array();
 
         if (self::setup()) {
-            foreach ((array)self::list_folders('', '*', $type) as $foldername) {
-                $folders[$foldername] = new kolab_storage_folder($foldername, self::$imap);
+            foreach ((array)self::list_folders('', '*', $type, false, $folderdata) as $foldername) {
+                $folders[$foldername] = new kolab_storage_folder($foldername, $folderdata[$foldername]);
             }
         }
 
@@ -92,7 +92,7 @@ class kolab_storage
      */
     public static function get_folder($folder)
     {
-        return self::setup() ? new kolab_storage_folder($folder, self::$imap) : null;
+        return self::setup() ? new kolab_storage_folder($folder) : null;
     }
 
 
@@ -110,7 +110,7 @@ class kolab_storage
         $folder = null;
         foreach ((array)self::list_folders('', '*', $type) as $foldername) {
             if (!$folder)
-                $folder = new kolab_storage_folder($foldername, self::$imap);
+                $folder = new kolab_storage_folder($foldername);
             else
                 $folder->set_folder($foldername);
 
@@ -384,10 +384,11 @@ class kolab_storage
      * @param string  Optional name pattern
      * @param string  Data type to list folders for (contact,distribution-list,event,task,note,mail)
      * @param string  Enable to return subscribed folders only
+     * @param array   Will be filled with folder-types data
      *
      * @return array List of folders
      */
-    public static function list_folders($root = '', $mbox = '*', $filter = null, $subscribed = false)
+    public static function list_folders($root = '', $mbox = '*', $filter = null, $subscribed = false, &$folderdata = array())
     {
         if (!self::setup()) {
             return null;
@@ -412,14 +413,14 @@ class kolab_storage
             return array();
         }
 
-        $regexp = '/^' . preg_quote($filter, '/') . '(\..+)?$/';
+        $folderdata = array_map('implode', $folderdata);
+        $regexp     = '/^' . preg_quote($filter, '/') . '(\..+)?$/';
 
         // In some conditions we can skip LIST command (?)
         if ($subscribed == false && $filter != 'mail' && $prefix == '*') {
-            foreach ($folderdata as $idx => $folder) {
-                $type = $folder[self::CTYPE_KEY];
+            foreach ($folderdata as $folder => $type) {
                 if (!preg_match($regexp, $type)) {
-                    unset($folderdata[$idx]);
+                    unset($folderdata[$folder]);
                 }
             }
             return array_keys($folderdata);
@@ -440,7 +441,7 @@ class kolab_storage
 
         // Filter folders list
         foreach ($folders as $idx => $folder) {
-            $type = !empty($folderdata[$folder]) ? $folderdata[$folder][self::CTYPE_KEY] : null;
+            $type = $folderdata[$folder];
 
             if ($filter == 'mail' && empty($type)) {
                 continue;
diff --git a/plugins/libkolab/lib/kolab_storage_folder.php b/plugins/libkolab/lib/kolab_storage_folder.php
index d6919064..ffbbb5d1 100644
--- a/plugins/libkolab/lib/kolab_storage_folder.php
+++ b/plugins/libkolab/lib/kolab_storage_folder.php
@@ -54,30 +54,34 @@ class kolab_storage_folder
     /**
      * Default constructor
      */
-    function __construct($name, $imap = null)
+    function __construct($name, $type = null)
     {
-        $this->imap = is_object($imap) ? $imap : rcube::get_instance()->get_storage();
+        $this->imap = rcube::get_instance()->get_storage();
         $this->imap->set_options(array('skip_deleted' => true));
         $this->cache = new kolab_storage_cache($this);
-        $this->set_folder($name);
+        $this->set_folder($name, $type);
     }
 
 
     /**
-     * Set the IMAP folder name this instance connects to
+     * Set the IMAP folder this instance connects to
      *
      * @param string The folder name/path
+     * @param string Optional folder type if known
      */
-    public function set_folder($name)
+    public function set_folder($name, $type = null)
     {
-        $this->name = $name;
+        if (!$type) {
+            $metadata = $this->imap->get_metadata($name, array(kolab_storage::CTYPE_KEY));
+            $type     = $metadata[$this->name][kolab_storage::CTYPE_KEY];
+        }
+
+        $this->name            = $name;
+        $this->type_annotation = $type;
+        $this->type            = reset(explode('.', $type));
+        $this->resource_uri    = null;
+
         $this->imap->set_folder($this->name);
-
-        $metadata = $this->imap->get_metadata($this->name, array(kolab_storage::CTYPE_KEY));
-        $this->type_annotation = $metadata[$this->name][kolab_storage::CTYPE_KEY];
-        $this->type = reset(explode('.', $this->type_annotation));
-        $this->resource_uri = null;
-
         $this->cache->set_folder($this);
     }