diff --git a/calendar/inc/class.calendar_uiforms.inc.php b/calendar/inc/class.calendar_uiforms.inc.php
index f2fd7a1eda..f0e9335e04 100644
--- a/calendar/inc/class.calendar_uiforms.inc.php
+++ b/calendar/inc/class.calendar_uiforms.inc.php
@@ -337,7 +337,9 @@ class calendar_uiforms extends calendar_ui
 			else
 			{
 				$content['alarm'][1]['offset'] = $offset = 60 * $def_alarm;
+				$content['start'] = $this->bo->date2array($content['start']);
 				$content['start'][1]['offset'] = $this->bo->date2ts($content['start']) - $offset;
+				$content['start'] = $this->bo->date2ts($content['start']);
 			}
 		}