diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index 8a8f7660..133dcac8 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -563,11 +563,11 @@ class calendar extends rcube_plugin
     $success = $reload = $got_msg = false;
     
     // don't notify if modifying a recurring instance (really?)
-    if ($event['savemode'] && $event['savemode'] != 'all' && $event['notify'])
-      unset($event['notify']);
+    if ($event['_savemode'] && $event['_savemode'] != 'all' && $event['_notify'])
+      unset($event['_notify']);
     
     // read old event data in order to find changes
-    if (($event['notify'] || $event['decline']) && $action != 'new')
+    if (($event['_notify'] || $event['decline']) && $action != 'new')
       $old = $this->driver->get_event($event);
 
     switch ($action) {
@@ -586,17 +586,17 @@ class calendar extends rcube_plugin
         $this->prepare_event($event, $action);
         if ($success = $this->driver->edit_event($event))
             $this->cleanup_event($event);
-        $reload =  $success && ($event['recurrence'] || $event['savemode'] || $event['fromcalendar']) ? 2 : 1;
+        $reload =  $success && ($event['recurrence'] || $event['_savemode'] || $event['_fromcalendar']) ? 2 : 1;
         break;
       
       case "resize":
         $success = $this->driver->resize_event($event);
-        $reload = $event['savemode'] ? 2 : 1;
+        $reload = $event['_savemode'] ? 2 : 1;
         break;
       
       case "move":
         $success = $this->driver->move_event($event);
-        $reload =  $success && $event['savemode'] ? 2 : 1;
+        $reload =  $success && $event['_savemode'] ? 2 : 1;
         break;
       
       case "remove":
@@ -613,7 +613,7 @@ class calendar extends rcube_plugin
         }
 
         $success = $this->driver->remove_event($event, $undo_time < 1);
-        $reload = (!$success || $event['savemode']) ? 2 : 1;
+        $reload = (!$success || $event['_savemode']) ? 2 : 1;
 
         if ($undo_time > 0 && $success) {
           $_SESSION['calendar_event_undo'] = array('ts' => time(), 'data' => $event);
@@ -728,7 +728,7 @@ class calendar extends rcube_plugin
     }
     
     // send out notifications
-    if ($success && $event['notify'] && ($event['attendees'] || $old['attendees'])) {
+    if ($success && $event['_notify'] && ($event['attendees'] || $old['attendees'])) {
       // make sure we have the complete record
       $event = $action == 'remove' ? $old : $this->driver->get_event($event);
       
diff --git a/plugins/calendar/calendar_ui.js b/plugins/calendar/calendar_ui.js
index e82d900f..92c5bb35 100644
--- a/plugins/calendar/calendar_ui.js
+++ b/plugins/calendar/calendar_ui.js
@@ -603,7 +603,7 @@ function rcube_calendar_ui(settings)
         
         // tell server to send notifications
         if (data.attendees.length && organizer && ((event.id && notify.checked) || (!event.id && invite.checked))) {
-          data.notify = 1;
+          data._notify = 1;
         }
 
         // gather recurrence settings
@@ -651,9 +651,9 @@ function rcube_calendar_ui(settings)
         if (event.id) {
           data.id = event.id;
           if (event.recurrence)
-            data.savemode = $('input.edit-recurring-savemode:checked').val();
+            data._savemode = $('input.edit-recurring-savemode:checked').val();
           if (data.calendar && data.calendar != event.calendar)
-            data.fromcalendar = event.calendar;
+            data._fromcalendar = event.calendar;
         }
 
         update_event(action, data);
@@ -1527,9 +1527,9 @@ function rcube_calendar_ui(settings)
         var $dialog = $('<div>').html(html);
       
         $dialog.find('a.button').button().click(function(e){
-          data.savemode = String(this.href).replace(/.+#/, '');
+          data._savemode = String(this.href).replace(/.+#/, '');
           if ($dialog.find('input.confirm-attendees-donotify').get(0))
-            data.notify = notify && $dialog.find('input.confirm-attendees-donotify').get(0).checked ? 1 : 0;
+            data._notify = notify && $dialog.find('input.confirm-attendees-donotify').get(0).checked ? 1 : 0;
           if (decline && $dialog.find('input.confirm-attendees-decline:checked'))
             data.decline = 1;
           update_event(action, data);
@@ -1548,7 +1548,7 @@ function rcube_calendar_ui(settings)
           buttons.push({
             text: rcmail.gettext((action == 'remove' ? 'remove' : 'save'), 'calendar'),
             click: function() {
-              data.notify = notify && $dialog.find('input.confirm-attendees-donotify').get(0).checked ? 1 : 0;
+              data._notify = notify && $dialog.find('input.confirm-attendees-donotify').get(0).checked ? 1 : 0;
               data.decline = decline && $dialog.find('input.confirm-attendees-decline:checked').length ? 1 : 0;
               update_event(action, data);
               $(this).dialog("close");
diff --git a/plugins/calendar/drivers/calendar_driver.php b/plugins/calendar/drivers/calendar_driver.php
index ac01aa29..3dd7806b 100644
--- a/plugins/calendar/drivers/calendar_driver.php
+++ b/plugins/calendar/drivers/calendar_driver.php
@@ -66,11 +66,11 @@
  *            'role' => 'ORGANIZER|REQ-PARTICIPANT|OPT-PARTICIPANT|CHAIR',
  *          'status' => 'NEEDS-ACTION|UNKNOWN|ACCEPTED|TENTATIVE|DECLINED'
  *            'rsvp' => true|false,
- *
- *      'savemode' => 'all|future|current|new',   // How changes on recurring event should be handled
- *        'notify' => true|false,  // whether to notify event attendees about changes
- *  'fromcalendar' => 'Calendar identifier where the event was stored before',
  *    ),
+ *
+ *     '_savemode' => 'all|future|current|new',   // How changes on recurring event should be handled
+ *       '_notify' => true|false,  // whether to notify event attendees about changes
+ * '_fromcalendar' => 'Calendar identifier where the event was stored before',
  *  );
  */
 
diff --git a/plugins/calendar/drivers/database/database_driver.php b/plugins/calendar/drivers/database/database_driver.php
index a3a712a7..f88ecb3f 100644
--- a/plugins/calendar/drivers/database/database_driver.php
+++ b/plugins/calendar/drivers/database/database_driver.php
@@ -281,7 +281,7 @@ class database_driver extends calendar_driver
         if ($old['recurrence']['EXDATE'])
           $event['recurrence']['EXDATE'] = $old['recurrence']['EXDATE'];
         
-        switch ($event['savemode']) {
+        switch ($event['_savemode']) {
           case 'new':
             $event['uid'] = $this->cal->generate_uid();
             return $this->new_event($event);
@@ -440,7 +440,7 @@ class database_driver extends calendar_driver
         $sql_set[] = $this->rc->db->quote_identifier($col) . '=' . $this->rc->db->quote($event[$col]);
     }
     
-    if ($event['fromcalendar'] && $event['fromcalendar'] != $event['calendar'])
+    if ($event['_fromcalendar'] && $event['_fromcalendar'] != $event['calendar'])
         $sql_set[] = 'calendar_id=' . $this->rc->db->quote($event['calendar']);
     
     $query = $this->rc->db->query(sprintf(
@@ -580,7 +580,7 @@ class database_driver extends calendar_driver
       // read master if deleting a recurring event
       if ($event['recurrence'] || $event['recurrence_id']) {
         $master = $event['recurrence_id'] ? $this->get_event(array('id' => $old['recurrence_id'])) : $event;
-        $savemode = $event['savemode'];
+        $savemode = $event['_savemode'];
       }
 
       switch ($savemode) {
diff --git a/plugins/calendar/drivers/kolab/kolab_driver.php b/plugins/calendar/drivers/kolab/kolab_driver.php
index d23b9d55..3e41426a 100644
--- a/plugins/calendar/drivers/kolab/kolab_driver.php
+++ b/plugins/calendar/drivers/kolab/kolab_driver.php
@@ -479,7 +479,7 @@ class kolab_driver extends calendar_driver
       // read master if deleting a recurring event
       if ($event['recurrence'] || $event['recurrence_id']) {
         $master = $event['recurrence_id'] ? $storage->get_event($event['recurrence_id']) : $event;
-        $savemode = $event['savemode'];
+        $savemode = $event['_savemode'];
       }
 
       switch ($savemode) {
@@ -538,11 +538,11 @@ class kolab_driver extends calendar_driver
       return false;
 
     // move event to another folder/calendar
-    if ($event['fromcalendar'] && $event['fromcalendar'] != $event['calendar']) {
-      if (!($fromcalendar = $this->calendars[$event['fromcalendar']]))
+    if ($event['_fromcalendar'] && $event['_fromcalendar'] != $event['calendar']) {
+      if (!($fromcalendar = $this->calendars[$event['_fromcalendar']]))
         return false;
 
-      if ($event['savemode'] != 'new') {
+      if ($event['_savemode'] != 'new') {
         if (!$fromcalendar->storage->move($event['id'], $storage->get_realname()))
           return false;
 
@@ -592,7 +592,7 @@ class kolab_driver extends calendar_driver
     // modify a recurring event, check submitted savemode to do the right things
     if ($old['recurrence'] || $old['recurrence_id']) {
       $master = $old['recurrence_id'] ? $fromcalendar->get_event($old['recurrence_id']) : $old;
-      $savemode = $event['savemode'];
+      $savemode = $event['_savemode'];
     }
 
     // keep saved exceptions (not submitted by the client)
diff --git a/plugins/calendar/lib/calendar_ui.php b/plugins/calendar/lib/calendar_ui.php
index abec75f7..f802091f 100644
--- a/plugins/calendar/lib/calendar_ui.php
+++ b/plugins/calendar/lib/calendar_ui.php
@@ -346,7 +346,7 @@ class calendar_ui
    */
   function edit_attendees_notify($attrib = array())
   {
-    $checkbox = new html_checkbox(array('name' => 'notify', 'id' => 'edit-attendees-donotify', 'value' => 1));
+    $checkbox = new html_checkbox(array('name' => '_notify', 'id' => 'edit-attendees-donotify', 'value' => 1));
     return html::div($attrib, html::label(null, $checkbox->show(1) . ' ' . $this->cal->gettext('sendnotifications')));
   }
 
@@ -357,7 +357,7 @@ class calendar_ui
   {
     $attrib['id'] = 'edit-recurring-warning';
     
-    $radio = new html_radiobutton(array('name' => 'savemode', 'class' => 'edit-recurring-savemode'));
+    $radio = new html_radiobutton(array('name' => '_savemode', 'class' => 'edit-recurring-savemode'));
     $form = html::label(null, $radio->show('', array('value' => 'current')) . $this->cal->gettext('currentevent')) . ' ' .
        html::label(null, $radio->show('', array('value' => 'future')) . $this->cal->gettext('futurevents')) . ' ' .
        html::label(null, $radio->show('all', array('value' => 'all')) . $this->cal->gettext('allevents')) . ' ' .