disable the 'deleting' of fixed option

lib/network/modules/components/Node.js

@@ -195,10 +195,6 @@ class Node {
         }
       }
     }
-    else if (allowDeletion === true) {
-      parentOptions.fixed = undefined;
-      delete parentOptions.fixed;
-    }
   }
 
   updateLabelModule() {