diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index 0e2e86ea..5c45518e 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -265,7 +265,7 @@ class calendar extends rcube_plugin
     $default_id = $this->rc->config->get('calendar_default_calendar');
     $calendars = $this->driver->list_calendars(calendar_driver::FILTER_PERSONAL);
     $calendar = $calendars[$default_id] ?: null;
-    if (!$calendar || $confidential || ($writeable && $calendar['readonly'])) {
+    if (!$calendar || $confidential || ($writeable && !$calendar['writeable'])) {
       foreach ($calendars as $cal) {
         if ($confidential && $cal['subtype'] == 'confidential') {
           $calendar = $cal;
@@ -276,7 +276,7 @@ class calendar extends rcube_plugin
           if (!$confidential)
             break;
         }
-        if (!$writeable || !$cal['readonly']) {
+        if (!$writeable || $cal['writeable']) {
           $first = $cal;
         }
       }
@@ -2459,7 +2459,7 @@ class calendar extends rcube_plugin
       $calendar_select->add('--', '');
       $numcals = 0;
       foreach ($calendars as $calendar) {
-        if (!$calendar['readonly']) {
+        if ($calendar['writeable']) {
           $calendar_select->add($calendar['name'], $calendar['id']);
           $numcals++;
         }
@@ -2840,7 +2840,7 @@ class calendar extends rcube_plugin
       }
       
       // save to calendar
-      if ($calendar && !$calendar['readonly']) {
+      if ($calendar && $calendar['writeable']) {
         // check for existing event with the same UID
         $existing = $this->driver->get_event($event, calendar_driver::FILTER_WRITEABLE | calendar_driver::FILTER_PERSONAL);
 
@@ -3107,7 +3107,7 @@ class calendar extends rcube_plugin
       foreach ($events as $event) {
         // save to calendar
         $calendar = $calendars[$cal_id] ?: $this->get_default_calendar(true, $event['sensitivity'] == 'confidential');
-        if ($calendar && !$calendar['readonly'] && $event['_type'] == 'event') {
+        if ($calendar && $calendar['writeable'] && $event['_type'] == 'event') {
           $event['calendar'] = $calendar['id'];
 
           if (!$this->driver->get_event($event['uid'], calendar_driver::FILTER_WRITEABLE)) {
diff --git a/plugins/calendar/calendar_ui.js b/plugins/calendar/calendar_ui.js
index 06e87593..9dd40141 100644
--- a/plugins/calendar/calendar_ui.js
+++ b/plugins/calendar/calendar_ui.js
@@ -63,7 +63,7 @@ function rcube_calendar_ui(settings)
     var resources_data = {};
     var resources_index = [];
     var resource_owners = {};
-    var resources_events_source = { url:null, editable:false };
+    var resources_events_source = { url:null, editable:false, insertable:false };
     var freebusy_ui = { workinhoursonly:false, needsupdate:false };
     var freebusy_data = {};
     var current_view = null;
@@ -392,7 +392,7 @@ function rcube_calendar_ui(settings)
     var event_show_dialog = function(event, ev, temp)
     {
       var $dialog = $("#eventshow");
-      var calendar = event.calendar && me.calendars[event.calendar] ? me.calendars[event.calendar] : { editable:false };
+      var calendar = event.calendar && me.calendars[event.calendar] ? me.calendars[event.calendar] : { editable:false, insertable:false };
 
       if (!temp)
         me.selected_event = event;
@@ -687,7 +687,7 @@ function rcube_calendar_ui(settings)
       $("#eventshow:ui-dialog").data('opener', null).dialog('close');
 
       var $dialog = $('<div>');
-      var calendar = event.calendar && me.calendars[event.calendar] ? me.calendars[event.calendar] : { editable:action=='new' };
+      var calendar = event.calendar && me.calendars[event.calendar] ? me.calendars[event.calendar] : { insertable:action=='new' };
       me.selected_event = $.extend($.extend({}, event_defaults), event);  // clone event object (with defaults)
       event = me.selected_event; // change reference to clone
       freebusy_ui.needsupdate = false;
@@ -734,6 +734,12 @@ function rcube_calendar_ui(settings)
         allday.checked = false;
       }
 
+      // set calendar selection according to permissions
+      calendars.find('option').each(function(i, opt) {
+        var cal = me.calendars[opt.value] || {};
+        $(opt).prop('disabled', !(cal.editable || (action == 'new' && cal.insertable)))
+      });
+
       // set alarm(s)
       me.set_alarms_edit('#edit-alarms', action != 'new' && event.valarms && calendar.alarms ? event.valarms : []);
 
@@ -808,7 +814,7 @@ function rcube_calendar_ui(settings)
       // attachments
       var load_attachments_tab = function()
       {
-        rcmail.enable_command('remove-attachment', !calendar.readonly && !event.recurrence_id);
+        rcmail.enable_command('remove-attachment', calendar.editable && !event.recurrence_id);
         rcmail.env.deleted_attachments = [];
         // we're sharing some code for uploads handling with app.js
         rcmail.env.attachments = [];
@@ -3553,7 +3559,8 @@ function rcube_calendar_ui(settings)
 
       me.calendars[id] = $.extend({
         url: rcmail.url('calendar/load_events', { source: id }),
-        editable: !cal.readonly,
+        editable: cal.writeable || false,
+        insertable: cal.insert || false,
         className: 'fc-event-cal-'+id,
         id: id
       }, cal);
@@ -3583,7 +3590,7 @@ function rcube_calendar_ui(settings)
 
       // insert to #calendar-select options if writeable
       select = $('#edit-calendar');
-      if (fc && !cal.readonly && select.length && !select.find('option[value="'+id+'"]').length) {
+      if (fc && (cal.writeable || cal.insert) && select.length && !select.find('option[value="'+id+'"]').length) {
         $('<option>').attr('value', id).html(cal.name).appendTo(select);
       }
     }
@@ -3618,7 +3625,7 @@ function rcube_calendar_ui(settings)
         count_sources.push(id);
       }
 
-      if (!cal.readonly && !this.selected_calendar) {
+      if (cal.writeable && !this.selected_calendar) {
         this.selected_calendar = id;
         rcmail.enable_command('addevent', true);
       }
@@ -3640,7 +3647,7 @@ function rcube_calendar_ui(settings)
       if (node && node.id && me.calendars[node.id]) {
         me.select_calendar(node.id, true);
         rcmail.enable_command('calendar-edit', 'calendar-showurl', true);
-        rcmail.enable_command('calendar-delete', !me.calendars[node.id].readonly);
+        rcmail.enable_command('calendar-delete', me.calendars[node.id].editable);
         rcmail.enable_command('calendar-remove', me.calendars[node.id] && me.calendars[node.id].removable);
       }
     });
@@ -3751,7 +3758,7 @@ function rcube_calendar_ui(settings)
     });
 
     // select default calendar
-    if (settings.default_calendar && this.calendars[settings.default_calendar] && !this.calendars[settings.default_calendar].readonly)
+    if (settings.default_calendar && this.calendars[settings.default_calendar] && this.calendars[settings.default_calendar].editable)
       this.selected_calendar = settings.default_calendar;
     
     if (this.selected_calendar)
@@ -3769,6 +3776,8 @@ function rcube_calendar_ui(settings)
         color: '#fff',
         textColor: '#333',
         editable: false,
+        writeable: false,
+        insertable: false,
         attendees: true
       };
       event_sources.push(me.calendars['--invitation--itip']);
diff --git a/plugins/calendar/drivers/calendar_driver.php b/plugins/calendar/drivers/calendar_driver.php
index da13ce66..b25f1c54 100644
--- a/plugins/calendar/drivers/calendar_driver.php
+++ b/plugins/calendar/drivers/calendar_driver.php
@@ -96,10 +96,11 @@ abstract class calendar_driver
 {
   const FILTER_ALL           = 0;
   const FILTER_WRITEABLE     = 1;
-  const FILTER_ACTIVE        = 2;
-  const FILTER_PERSONAL      = 4;
-  const FILTER_PRIVATE       = 8;
-  const FILTER_CONFIDENTIAL  = 16;
+  const FILTER_INSERTABLE    = 2;
+  const FILTER_ACTIVE        = 4;
+  const FILTER_PERSONAL      = 8;
+  const FILTER_PRIVATE       = 16;
+  const FILTER_CONFIDENTIAL  = 32;
   const BIRTHDAY_CALENDAR_ID = '__bdays__';
 
   // features supported by backend
diff --git a/plugins/calendar/drivers/database/database_driver.php b/plugins/calendar/drivers/database/database_driver.php
index 10eae038..e3f7fc87 100644
--- a/plugins/calendar/drivers/database/database_driver.php
+++ b/plugins/calendar/drivers/database/database_driver.php
@@ -89,6 +89,8 @@ class database_driver extends calendar_driver
         $arr['active']     = !in_array($arr['id'], $hidden);
         $arr['name']       = html::quote($arr['name']);
         $arr['listname']   = html::quote($arr['name']);
+        $arr['insert']     = true;
+        $arr['writeable']  = true;
         $this->calendars[$arr['calendar_id']] = $arr;
         $calendar_ids[] = $this->rc->db->quote($arr['calendar_id']);
       }
@@ -139,7 +141,7 @@ class database_driver extends calendar_driver
           'showalarms' => (bool)$this->rc->config->get('calendar_birthdays_alarm_type'),
           'active'     => !in_array($id, $hidden),
           'group'      => 'x-birthdays',
-          'readonly'   => true,
+          'writeable'  => false,
           'default'    => false,
           'children'   => false,
         );
diff --git a/plugins/calendar/drivers/kolab/kolab_calendar.php b/plugins/calendar/drivers/kolab/kolab_calendar.php
index ae96efad..3ea8094a 100644
--- a/plugins/calendar/drivers/kolab/kolab_calendar.php
+++ b/plugins/calendar/drivers/kolab/kolab_calendar.php
@@ -27,7 +27,8 @@
 class kolab_calendar extends kolab_storage_folder_api
 {
   public $ready = false;
-  public $readonly = true;
+  public $writeable = false;
+  public $insert = false;
   public $attachments = true;
   public $alarms = false;
   public $history = false;
@@ -78,17 +79,20 @@ class kolab_calendar extends kolab_storage_folder_api
     $this->storage = kolab_storage::get_folder($this->name);
     $this->ready = $this->storage && $this->storage->valid;
 
-    // Set readonly and alarms flags according to folder permissions
+    // Set writeable and alarms flags according to folder permissions
     if ($this->ready) {
       if ($this->storage->get_namespace() == 'personal') {
-        $this->readonly = false;
+        $this->writeable = true;
+        $this->insert = true;
         $this->alarms = true;
       }
       else {
         $rights = $this->storage->get_myrights();
         if ($rights && !PEAR::isError($rights)) {
-          if (strpos($rights, 'i') !== false)
-            $this->readonly = false;
+          if (strpos($rights, 'i') !== false || strpos($rights, 'w') !== false)
+            $this->insert = true;
+          if (strpos($rights, 't') !== false || strpos($rights, 'd') !== false)
+            $this->writeable = $this->insert;
         }
       }
       
diff --git a/plugins/calendar/drivers/kolab/kolab_driver.php b/plugins/calendar/drivers/kolab/kolab_driver.php
index db8d0f8e..3a111ab8 100644
--- a/plugins/calendar/drivers/kolab/kolab_driver.php
+++ b/plugins/calendar/drivers/kolab/kolab_driver.php
@@ -103,7 +103,7 @@ class kolab_driver extends calendar_driver
 
       if ($calendar->ready) {
         $this->calendars[$calendar->id] = $calendar;
-        if (!$calendar->readonly)
+        if ($calendar->writeable)
           $this->has_writeable = true;
       }
     }
@@ -173,9 +173,9 @@ class kolab_driver extends calendar_driver
           'owner'    => $cal->get_owner(),
           'history'  => false,
           'virtual'  => false,
-          'readonly' => true,
-          'group'    => 'other',
-          'class'    => 'user',
+          'writeable' => false,
+          'group'     => 'other',
+          'class'     => 'user',
           'removable' => true,
         );
       }
@@ -185,10 +185,10 @@ class kolab_driver extends calendar_driver
           'name' => $fullname,
           'listname' => $listname,
           'editname' => $cal->get_foldername(),
-          'virtual' => true,
-          'readonly' => true,
-          'group'    => $cal->get_namespace(),
-          'class'    => 'folder',
+          'virtual'  => true,
+          'writeable' => false,
+          'group'     => $cal->get_namespace(),
+          'class'     => 'folder',
         );
       }
       else {
@@ -199,7 +199,8 @@ class kolab_driver extends calendar_driver
           'editname' => $cal->get_foldername(),
           'title'    => $cal->get_title(),
           'color'    => $cal->get_color(),
-          'readonly' => $cal->readonly,
+          'writeable' => $cal->writeable,
+          'insert'    => $cal->insert,
           'showalarms' => $cal->alarms,
           'history'  => !empty($this->bonnie_api),
           'group'    => $cal->get_namespace(),
@@ -232,7 +233,8 @@ class kolab_driver extends calendar_driver
             'editname' => $cal->get_foldername(),
             'title'    => $cal->get_title(),
             'color'    => $cal->get_color(),
-            'readonly' => $cal->readonly,
+            'writeable' => $cal->writeable,
+            'insert'   => $cal->insert,
             'showalarms' => $cal->alarms,
             'history'  => !empty($this->bonnie_api),
             'group'    => 'x-invitations',
@@ -266,7 +268,7 @@ class kolab_driver extends calendar_driver
           'active'     => (bool)$prefs[$id]['active'],
           'showalarms' => (bool)$this->rc->config->get('calendar_birthdays_alarm_type'),
           'group'      => 'x-birthdays',
-          'readonly'   => true,
+          'writeable'  => false,
           'default'    => false,
           'children'   => false,
           'history'    => false,
@@ -293,6 +295,7 @@ class kolab_driver extends calendar_driver
       'calendars' => $calendars,
       'filter'    => $filter,
       'writeable' => ($filter & self::FILTER_WRITEABLE),
+      'insert'    => ($filter & self::FILTER_INSERTABLE),
       'active'    => ($filter & self::FILTER_ACTIVE),
       'personal'  => ($filter & self::FILTER_PERSONAL),
     ));
@@ -305,7 +308,10 @@ class kolab_driver extends calendar_driver
       if (!$cal->ready) {
         continue;
       }
-      if (($filter & self::FILTER_WRITEABLE) && $cal->readonly) {
+      if (($filter & self::FILTER_WRITEABLE) && !$cal->writeable) {
+        continue;
+      }
+      if (($filter & self::FILTER_INSERTABLE) && !$cal->insert) {
         continue;
       }
       if (($filter & self::FILTER_ACTIVE) && !$cal->is_active()) {
diff --git a/plugins/calendar/drivers/kolab/kolab_invitation_calendar.php b/plugins/calendar/drivers/kolab/kolab_invitation_calendar.php
index 2d2a63cc..a5c32c42 100644
--- a/plugins/calendar/drivers/kolab/kolab_invitation_calendar.php
+++ b/plugins/calendar/drivers/kolab/kolab_invitation_calendar.php
@@ -26,7 +26,7 @@ class kolab_invitation_calendar
   public $id = '__invitation__';
   public $ready = true;
   public $alarms = false;
-  public $readonly = true;
+  public $writeable = false;
   public $attachments = false;
   public $subscriptions = false;
   public $partstats = array('unknown');
diff --git a/plugins/calendar/drivers/kolab/kolab_user_calendar.php b/plugins/calendar/drivers/kolab/kolab_user_calendar.php
index 78461888..17656a24 100644
--- a/plugins/calendar/drivers/kolab/kolab_user_calendar.php
+++ b/plugins/calendar/drivers/kolab/kolab_user_calendar.php
@@ -25,7 +25,7 @@ class kolab_user_calendar extends kolab_calendar
 {
   public $id = 'unknown';
   public $ready = false;
-  public $readonly = true;
+  public $writeable = false;
   public $attachments = false;
   public $subscriptions = false;
 
diff --git a/plugins/calendar/lib/calendar_ui.php b/plugins/calendar/lib/calendar_ui.php
index 00b74cd1..825f42cd 100644
--- a/plugins/calendar/lib/calendar_ui.php
+++ b/plugins/calendar/lib/calendar_ui.php
@@ -294,7 +294,7 @@ class calendar_ui
 
     if ($prop['virtual'])
       $classes[] = 'virtual';
-    else if ($prop['readonly'])
+    else if (!$prop['writeable'])
       $classes[] = 'readonly';
     if ($prop['subscribed'])
       $classes[] = 'subscribed';
@@ -361,7 +361,7 @@ class calendar_ui
     $select = new html_select($attrib);
 
     foreach ((array)$this->cal->driver->list_calendars() as $id => $prop) {
-      if (!$prop['readonly'])
+      if (!empty($prop['insert']))
         $select->add($prop['name'], $id);
     }