diff --git a/mozilla/calendar/base/themes/pinstripe/calendar-views.css b/mozilla/calendar/base/themes/pinstripe/calendar-views.css
index 5fb0f53be6d..386eaf8bbf7 100644
--- a/mozilla/calendar/base/themes/pinstripe/calendar-views.css
+++ b/mozilla/calendar/base/themes/pinstripe/calendar-views.css
@@ -516,8 +516,8 @@ calendar-event-box[orient="horizontal"] .calendar-event-box-grippy-bottom {
     visibility: hidden;
 }
 
-calendar-event-box[readOnly="true"]:hover .calendar-event-box-grippy-top,
-calendar-event-box[readOnly="true"]:hover .calendar-event-box-grippy-bottom {
+calendar-event-box[readonly="true"]:hover .calendar-event-box-grippy-top,
+calendar-event-box[readonly="true"]:hover .calendar-event-box-grippy-bottom {
     visibility: hidden;
     cursor: auto;
 }
diff --git a/mozilla/calendar/base/themes/winstripe/calendar-views.css b/mozilla/calendar/base/themes/winstripe/calendar-views.css
index 7f7fae8c7ca..d0f4711a96e 100644
--- a/mozilla/calendar/base/themes/winstripe/calendar-views.css
+++ b/mozilla/calendar/base/themes/winstripe/calendar-views.css
@@ -516,8 +516,8 @@ calendar-event-box[orient="horizontal"] .calendar-event-box-grippy-bottom {
     visibility: hidden;
 }
 
-calendar-event-box[readOnly="true"]:hover .calendar-event-box-grippy-top,
-calendar-event-box[readOnly="true"]:hover .calendar-event-box-grippy-bottom {
+calendar-event-box[readonly="true"]:hover .calendar-event-box-grippy-top,
+calendar-event-box[readonly="true"]:hover .calendar-event-box-grippy-bottom {
     visibility: hidden;
     cursor: auto;
 }