--- a/calendar/base/modules/calProviderUtils.jsm
+++ b/calendar/base/modules/calProviderUtils.jsm
@@ -527,28 +527,16 @@ cal.ProviderBase.prototype = {
             if (!cal.ProviderBase.mTransientProperties[aName]) {
                 let value = this.mProperties[aName];
                 if (value !== null) {
                     calMgr.setCalendarPref_(this, aName, value);
                 }
             }
         }
 
-        let takeOverIfNotPresent = (oldPref, newPref, dontDeleteOldPref) => {
-            let val = calMgr.getCalendarPref_(this, oldPref);
-            if (val !== null) {
-                if (!dontDeleteOldPref) {
-                    calMgr.deleteCalendarPref_(this, oldPref);
-                }
-                if (calMgr.getCalendarPref_(this, newPref) === null) {
-                    calMgr.setCalendarPref_(this, newPref, val);
-                }
-            }
-        };
-
         // takeover lightning calendar visibility from 0.5:
         takeOverIfNotPresent("lightning-main-in-composite", "calendar-main-in-composite");
         takeOverIfNotPresent("lightning-main-default", "calendar-main-default");
 
         return aValue;
     },
 
     // attribute AUTF8String name;