Fix for U4-7260 - Multi node tree picker with no selection can cause a error to display in the backoffice

src/Umbraco.Web.UI.Client/src/common/resources/entity.resource.js

@@ -139,6 +139,12 @@ function entityResource($q, $http, umbRequestHelper) {
             _.each(ids, function(item) {
                 query += "ids=" + item + "&";
             });
+
+            // if ids array is empty we need a empty variable in the querystring otherwise the service returns a error
+            if (ids.length === 0) {
+                query += "ids=&";
+            }
+
             query += "type=" + type;
 
             return umbRequestHelper.resourcePromise(