diff --git a/plugins/kolab_core/kolab_core.php b/plugins/kolab_core/kolab_core.php
index 425efa83..8ff82e87 100644
--- a/plugins/kolab_core/kolab_core.php
+++ b/plugins/kolab_core/kolab_core.php
@@ -2,7 +2,7 @@
 
 /**
  * Kolab core library
- * 
+ *
  * Plugin to setup a basic environment for interaction with a Kolab server.
  * Other Kolab-related plugins will depend on it and can use the static API rcube_core
  *
@@ -29,8 +29,8 @@ class kolab_core extends rcube_plugin
         $include_path = $this->home . PATH_SEPARATOR . ini_get('include_path');
         set_include_path($include_path);
 
-	// Register password reset hook
-	$this->add_hook('password_change', array($this, 'password_change'));
+        // Register password reset hook
+        $this->add_hook('password_change', array($this, 'password_change'));
     }
 
     /**
@@ -38,9 +38,9 @@ class kolab_core extends rcube_plugin
      */
     public function password_change($args)
     {
-	rcmail::get_instance()->session->remove('__auth');
+        rcmail::get_instance()->session->remove('__auth');
 
-	return $args;
+        return $args;
     }
 }
 
diff --git a/plugins/kolab_core/rcube_kolab.php b/plugins/kolab_core/rcube_kolab.php
index a54776f5..c773a93d 100644
--- a/plugins/kolab_core/rcube_kolab.php
+++ b/plugins/kolab_core/rcube_kolab.php
@@ -27,7 +27,7 @@ require_once 'Horde/Perms.php';
 class rcube_kolab
 {
     public static $last_error;
-    
+
     private static $horde_auth;
     private static $config;
     private static $ready = false;
@@ -102,7 +102,7 @@ class rcube_kolab
             self::$ready = true;
         }
         else {
-    	    raise_error(array(
+            raise_error(array(
                 'code' => 600, 'type' => 'php',
                 'file' => __FILE__, 'line' => __LINE__,
                 'message' => sprintf("Unable to authenticate user %s!", $_SESSION['username'])),
@@ -197,19 +197,19 @@ class rcube_kolab
     public static function is_subscribed($folder)
     {
       static $subscribed;  // local cache
-      
+
       if (!$subscribed) {
         $rcmail = rcmail::get_instance();
         // try without connection first (list could be served from cache)
         $subscribed = $rcmail->imap ? $rcmail->imap->list_mailboxes() : array();
-        
+
         // now really get the list from the IMAP server
         if (empty($subscribed) || $subscribed == array('INBOX')) {
           $rcmail->imap_connect();
           $subscribed = $rcmail->imap->list_mailboxes();
         }
       }
-      
+
       return in_array($folder, $subscribed);
     }