diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index 403f00c6..035fdc0f 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -1409,7 +1409,7 @@ class calendar extends rcube_plugin
         $status = self::FREEBUSY_FREE;
         foreach ($fblist as $slot) {
           list($from, $to, $type) = $slot;
-          if ($from <= $t_end && $to > $t) {
+          if ($from < $t_end && $to > $t) {
             $status = isset($type) ? $type : self::FREEBUSY_BUSY;
             break;
           }
diff --git a/plugins/calendar/calendar_ui.js b/plugins/calendar/calendar_ui.js
index 99596346..f29ea27d 100644
--- a/plugins/calendar/calendar_ui.js
+++ b/plugins/calendar/calendar_ui.js
@@ -1538,12 +1538,17 @@ function rcube_calendar_ui(settings)
         .data('id', id);
       }
       
-      if (!cal.readonly && !this.selected_calendar && (!settings.default_calendar || settings.default_calendar == id)) {
+      if (!cal.readonly && !this.selected_calendar) {
         this.selected_calendar = id;
         rcmail.enable_command('addevent', true);
       }
     }
-
+    
+    // select default calendar
+    if (settings.default_calendar && this.calendars[settings.default_calendar] && !this.calendars[settings.default_calendar].readonly)
+      this.selected_calendar = settings.default_calendar;
+    
+    
     // initalize the fullCalendar plugin
     var fc = $('#calendar').fullCalendar({
       header: {