diff --git a/plugins/libkolab/lib/kolab_format_event.php b/plugins/libkolab/lib/kolab_format_event.php
index 6af8f0d9..c48b63d5 100644
--- a/plugins/libkolab/lib/kolab_format_event.php
+++ b/plugins/libkolab/lib/kolab_format_event.php
@@ -27,8 +27,6 @@ class kolab_format_event extends kolab_format_xcal
     protected $read_func = 'kolabformat::readEvent';
     protected $write_func = 'kolabformat::writeEvent';
 
-    public static $fulltext_cols = array('title', 'description', 'location', 'attendees:name', 'attendees:email');
-
     private $kolab2_rolemap = array(
         'required' => 'REQ-PARTICIPANT',
         'optional' => 'OPT-PARTICIPANT',
@@ -181,34 +179,6 @@ class kolab_format_event extends kolab_format_xcal
         return $tags;
     }
 
-    /**
-     * Callback for kolab_storage_cache to get words to index for fulltext search
-     *
-     * @return array List of words to save in cache
-     */
-    public function get_words()
-    {
-        $data = '';
-        foreach (self::$fulltext_cols as $colname) {
-            list($col, $field) = explode(':', $colname);
-
-            if ($field) {
-                $a = array();
-                foreach ((array)$this->data[$col] as $attr)
-                    $a[] = $attr[$field];
-                $val = join(' ', $a);
-            }
-            else {
-                $val = is_array($this->data[$col]) ? join(' ', $this->data[$col]) : $this->data[$col];
-            }
-
-            if (strlen($val))
-                $data .= $val . ' ';
-        }
-
-        return array_unique(rcube_utils::normalize_string($data, true));
-    }
-
     /**
      * Load data from old Kolab2 format
      */
diff --git a/plugins/libkolab/lib/kolab_format_task.php b/plugins/libkolab/lib/kolab_format_task.php
index d7bb275e..477f1b2d 100644
--- a/plugins/libkolab/lib/kolab_format_task.php
+++ b/plugins/libkolab/lib/kolab_format_task.php
@@ -123,4 +123,24 @@ class kolab_format_task extends kolab_format_xcal
         $this->data = $object;
     }
 
+    /**
+     * Callback for kolab_storage_cache to get object specific tags to cache
+     *
+     * @return array List of tags to save in cache
+     */
+    public function get_tags()
+    {
+        $tags = array();
+
+        if ($this->data['status'] == 'COMPLETED' || $this->data['complete'] == 100)
+            $tags[] = 'complete';
+
+        if ($this->data['priority'] == 1)
+            $tags[] = 'flagged';
+
+        if (!empty($this->data['alarms']))
+            $tags[] = 'x-has-alarms';
+
+        return $tags;
+    }
 }
diff --git a/plugins/libkolab/lib/kolab_format_xcal.php b/plugins/libkolab/lib/kolab_format_xcal.php
index 19d29215..db2ad3a6 100644
--- a/plugins/libkolab/lib/kolab_format_xcal.php
+++ b/plugins/libkolab/lib/kolab_format_xcal.php
@@ -28,6 +28,8 @@ abstract class kolab_format_xcal extends kolab_format
 {
     public $CTYPE = 'application/calendar+xml';
 
+    public static $fulltext_cols = array('title', 'description', 'location', 'attendees:name', 'attendees:email');
+
     protected $sensitivity_map = array(
         'public'       => kolabformat::ClassPublic,
         'private'      => kolabformat::ClassPrivate,
@@ -358,4 +360,32 @@ abstract class kolab_format_xcal extends kolab_format
         $this->obj->setAlarms($valarms);
     }
 
+    /**
+     * Callback for kolab_storage_cache to get words to index for fulltext search
+     *
+     * @return array List of words to save in cache
+     */
+    public function get_words()
+    {
+        $data = '';
+        foreach (self::$fulltext_cols as $colname) {
+            list($col, $field) = explode(':', $colname);
+
+            if ($field) {
+                $a = array();
+                foreach ((array)$this->data[$col] as $attr)
+                    $a[] = $attr[$field];
+                $val = join(' ', $a);
+            }
+            else {
+                $val = is_array($this->data[$col]) ? join(' ', $this->data[$col]) : $this->data[$col];
+            }
+
+            if (strlen($val))
+                $data .= $val . ' ';
+        }
+
+        return array_unique(rcube_utils::normalize_string($data, true));
+    }
+
 }
\ No newline at end of file
diff --git a/plugins/libkolab/lib/kolab_storage_cache.php b/plugins/libkolab/lib/kolab_storage_cache.php
index d1ec64e4..9d4b37e6 100644
--- a/plugins/libkolab/lib/kolab_storage_cache.php
+++ b/plugins/libkolab/lib/kolab_storage_cache.php
@@ -383,8 +383,9 @@ class kolab_storage_cache
                 $qvalue = '(' . join(',', array_map(array($this->db, 'quote'), $param[2])) . ')';
                 $param[1] = 'IN';
             }
-            else if ($param[1] == '~' || $param[1] == 'LIKE') {
-                $param[1] = 'LIKE';
+            else if ($param[1] == '~' || $param[1] == 'LIKE' || $param[1] == '!~' || $param[1] == '!LIKE') {
+                $not = ($param[1] == '!~' || $param[1] == '!LIKE') ? 'NOT ' : '';
+                $param[1] = $not . 'LIKE';
                 $qvalue = $this->db->quote('%'.preg_replace('/(^\^|\$$)/', ' ', $param[2]).'%');
             }
             else if ($param[0] == 'tags') {