Issue #2312925 by olli, kim.pepper, dawehner: Fixed 'Add Link' button adds a new menu instead.

core/modules/menu_ui/menu_ui.module

@@ -75,7 +75,8 @@ function menu_ui_entity_type_build(array &$entity_types) {
     ->setListBuilderClass('Drupal\menu_ui\MenuListBuilder')
     ->setLinkTemplate('add-form', 'menu_ui.menu_add')
     ->setLinkTemplate('delete-form', 'menu_ui.delete_menu')
-    ->setLinkTemplate('edit-form', 'menu_ui.menu_edit');
+    ->setLinkTemplate('edit-form', 'menu_ui.menu_edit')
+    ->setLinkTemplate('add-link-form', 'menu_link_content.link_add');
 }
 
 

core/modules/menu_ui/src/MenuListBuilder.php

@@ -54,7 +54,7 @@ public function getDefaultOperations(EntityInterface $entity) {
       $operations['add'] = array(
         'title' => t('Add link'),
         'weight' => 20,
-      ) + $entity->urlInfo('add-form')->toArray();
+      ) + $entity->urlInfo('add-link-form')->toArray();
     }
     if (isset($operations['delete'])) {
       $operations['delete']['title'] = t('Delete menu');

core/modules/menu_ui/src/Tests/MenuTest.php

@@ -249,6 +249,10 @@ function doMenuTests() {
       ),
     ));
 
+    // Verify add link button.
+    $this->drupalGet('admin/structure/menu');
+    $this->assertLinkByHref('admin/structure/menu/manage/' . $menu_name . '/add', 0, "The add menu link button url is correct");
+
     // Add menu links.
     $item1 = $this->addMenuLink('', 'node/' . $node1->id(), $menu_name, TRUE);
     $item2 = $this->addMenuLink($item1->getPluginId(), 'node/' . $node2->id(), $menu_name, FALSE);