diff --git a/calendar/lib.php b/calendar/lib.php
index 7da4e0ee0ee..994e499525d 100644
--- a/calendar/lib.php
+++ b/calendar/lib.php
@@ -366,7 +366,7 @@ function calendar_get_mini($courses, $groups, $users, $cal_month = false, $cal_y
             } else if(isset($typesbyday[$day]['startuser'])) {
                 $class .= ' calendar_event_user';
             }
-            $cell = html_writer::link($dayhref, $day, array('aria-controls' => $popupid.'_panel', 'id' => $popupid));
+            $cell = html_writer::link($dayhref, $day, array('id' => $popupid));
         } else {
             $cell = $day;
         }
@@ -409,7 +409,7 @@ function calendar_get_mini($courses, $groups, $users, $cal_month = false, $cal_y
             if(! isset($eventsbyday[$day])) {
                 $class .= ' eventnone';
                 $popupid = calendar_get_popup(true, false);
-                $cell = html_writer::link('#', $day, array('aria-controls' => $popupid.'_panel', 'id' => $popupid));
+                $cell = html_writer::link('#', $day, array('id' => $popupid));
             }
             $cell = get_accesshide($today.' ').$cell;
         }
diff --git a/calendar/yui/eventmanager/eventmanager.js b/calendar/yui/eventmanager/eventmanager.js
index 4aedc2e6ee5..255ab2ba281 100644
--- a/calendar/yui/eventmanager/eventmanager.js
+++ b/calendar/yui/eventmanager/eventmanager.js
@@ -48,6 +48,7 @@ YUI.add('moodle-calendar-eventmanager', function(Y) {
                     width : Math.floor(constraint.get('offsetWidth')*0.9)+"px"
                 });
                 panel.render(td);
+                node.setAttribute('aria-controls', panel.get('id'));
                 panel.get('boundingBox').addClass('calendar-event-panel');
                 panel.get('boundingBox').setAttribute('aria-live', 'off');
                 this.on('showevent', panel.show, panel);