diff --git a/calendar/js/et2_widget_event.js b/calendar/js/et2_widget_event.js
index 05b04ff669..5fc9841072 100644
--- a/calendar/js/et2_widget_event.js
+++ b/calendar/js/et2_widget_event.js
@@ -331,10 +331,14 @@ var et2_calendar_event = et2_valueWidget.extend([et2_IDetachedDOM],
 			'<span class="calendar_calEventLabel">'+this.egw().lang('End') + '</span>:' + end
 		var cat = et2_createWidget('select-cat',{'readonly':true},this);
 		cat.set_value(this.options.value.category);
-		var cat_label = [];
-		cat.span.children().each(function() {
-			cat_label.push($j(this).text());
-		});
+		var cat_label = this.options.value.category.indexOf(',') <= 0 ? cat.span.text() : [];
+		if(typeof cat_label != 'string')
+		{
+			cat.span.children().each(function() {
+				cat_label.push($j(this).text());
+			});
+			cat_label = cat_label.join(', ');
+		}
 		cat.destroy();
 		
 		return '<div class="calendar_calEventTooltip ' + this._status_class() + '" style="border-color: '+border+'; background: '+bg_color+';">'+
@@ -349,7 +353,7 @@ var et2_calendar_event = et2_valueWidget.extend([et2_IDetachedDOM],
 				this.options.value.description+'</p>'+
 				'<p style="margin: 2px 0px;">'+times+'</p>'+
 				(this.options.value.location ? '<p><span class="calendar_calEventLabel">'+this.egw().lang('Location') + '</span>:' + this.options.value.location+'</p>' : '')+
-				(cat_label ? '<p><span class="calendar_calEventLabel">'+this.egw().lang('Category') + '</span>:' + cat_label.join(', ')+'</p>' : '')+
+				(cat_label ? '<p><span class="calendar_calEventLabel">'+this.egw().lang('Category') + '</span>:' + cat_label +'</p>' : '')+
 				'<p><span class="calendar_calEventLabel">'+this.egw().lang('Participants')+'</span>:<br />'+
 					(this.options.value.parts ? this.options.value.parts.replace("\n","<br />"):'')+'</p>'+
 			'</div>'+