diff --git a/calendar/js/et2_widget_event.js b/calendar/js/et2_widget_event.js
index da8d747ca6..8a707d0dfa 100644
--- a/calendar/js/et2_widget_event.js
+++ b/calendar/js/et2_widget_event.js
@@ -636,14 +636,17 @@ var et2_calendar_event = et2_valueWidget.extend([et2_IDetachedDOM],
 		var owner_match = true;
 		if(event.participants && this._parent.options.owner)
 		{
-			var parent_owner = this._parent.options.owner;
+			var parent_owner = typeof this._parent.options.owner !== 'object' ?
+				[this._parent.options.owner] :
+				this._parent.options.owner;
 			owner_match = false;
-			for(var i = 0; i < this._parent.options.owner.length; i++ )
+			var length = parent_owner.length;
+			for(var i = 0; i < length; i++ )
 			{
-				if (parseInt(this._parent.options.owner[i]) < 0)
+				if (parseInt(parent_owner[i]) < 0)
 				{
 					// Add in groups, if we can get them (this is syncronous)
-					egw.accountData(this._parent.options.owner[i],'account_id',true,function(members) {
+					egw.accountData(parent_owner[i],'account_id',true,function(members) {
 						parent_owner = parent_owner.concat(Object.keys(members));
 					});
 				}
diff --git a/calendar/js/et2_widget_timegrid.js b/calendar/js/et2_widget_timegrid.js
index b4a9971e3c..d60520f428 100644
--- a/calendar/js/et2_widget_timegrid.js
+++ b/calendar/js/et2_widget_timegrid.js
@@ -1365,9 +1365,11 @@ var et2_calendar_timegrid = et2_calendar_view.extend([et2_IDetachedDOM, et2_IRes
 		}
 
 		if(this.isAttached() && (
-			typeof old == "number" && typeof _owner == "number" && old !== this.options.owner ||
+			typeof old === "number" && typeof _owner === "number" && old !== this.options.owner ||
 			// Array of ids will not compare as equal
-			((typeof old === 'object' || typeof _owner === 'object') && old.toString() !== _owner.toString())
+			((typeof old === 'object' || typeof _owner === 'object') && old.toString() !== _owner.toString()) ||
+			// Strings
+			typeof old === 'string' && ''+old !== ''+this.options.owner
 		))
 		{
 			this.invalidate(true);