diff --git a/src/App.js b/src/App.js
index 426b672b97de64022f1023c693f2005a25098786..61e39aef7668471718f5bc42d9f6bc26e962977f 100644
--- a/src/App.js
+++ b/src/App.js
@@ -27,10 +27,8 @@ class App extends React.Component {
       }).catch(console.log('contact to the server'))       
     }
 
-    // (part 2) method to check whether param1 (=list) contains param2 (=comparable). 
-    // (part 3 update) this is obsolete due to changes in addPerson()-method
     isUnique = (list,comparable) =>{
-      var unique = list.filter(a=> comparable===a.name)
+      var unique = list.filter(a=> comparable.toUpperCase() ===a.name.toUpperCase())
       if(unique.length>0){
         return false
       }