diff --git a/calendar/js/et2_widget_event.js b/calendar/js/et2_widget_event.js
index 0905a21a79..5204b8c46e 100644
--- a/calendar/js/et2_widget_event.js
+++ b/calendar/js/et2_widget_event.js
@@ -999,7 +999,16 @@ et2_calendar_event.recur_prompt = function(event_data, callback, extra_data)
 {
 	var edit_id = event_data.app_id;
 	var edit_date = event_data.start;
+
+	// seems window.opener somehow in certian conditions could be from different origin
+	// we try to catch the exception and in this case retrive the egw object from current window.
+	try {
 	var egw = this.egw ? (typeof this.egw == 'function' ? this.egw() : this.egw) : window.opener && typeof window.opener.egw != 'undefined' ? window.opener.egw('calendar'):window.egw('calendar');
+	}
+	catch(e){
+		var egw = window.egw('calendar');
+	}
+
 	var that = this;
 
 	var extra_params = extra_data && typeof extra_data == 'object' ? extra_data : {};
@@ -1063,7 +1072,15 @@ et2_calendar_event.recur_prompt = function(event_data, callback, extra_data)
  */
 et2_calendar_event.series_split_prompt = function(event_data, instance_date, callback)
 {
+	// seems window.opener somehow in certian conditions could be from different origin
+	// we try to catch the exception and in this case retrive the egw object from current window.
+	try {
 	var egw = this.egw ? (typeof this.egw == 'function' ? this.egw() : this.egw) : window.opener && typeof window.opener.egw != 'undefined' ? window.opener.egw('calendar'):window.egw('calendar');
+	}
+	catch(e){
+		var egw = window.egw('calendar');
+	}
+
 	var that = this;
 
 	if(typeof instance_date == 'string')