Fixes JS with the content picker

src/Umbraco.Web.UI.Client/src/common/services/umbrequesthelper.service.js

@@ -161,6 +161,10 @@ function umbRequestHelper($http, $q, notificationsService, eventsService, formHe
 
             }, function (response) {
 
+                if (!response) {
+                    return; //sometimes oddly this happens, nothing we can do
+                }
+
                 if (!response.status && response.message && response.stack) {
                     //this is a JS/angular error that we should deal with
                     return $q.reject({

src/Umbraco.Web.UI.Client/src/views/propertyeditors/contentpicker/contentpicker.controller.js

@@ -105,6 +105,10 @@ function contentPickerController($scope, entityResource, editorState, iconHelper
     };
 
     if ($scope.model.config) {
+        //special case, if the `startNode` is falsy on the server config delete it entirely so the default value is merged in
+        if (!$scope.model.config.startNode) {
+            delete $scope.model.config.startNode;
+        }
         //merge the server config on top of the default config, then set the server config to use the result
         $scope.model.config = angular.extend(defaultConfig, $scope.model.config);
     }