Issue #2203835 by longwave: Make default form display and display mode be first secondary tabs.

core/modules/field_ui/lib/Drupal/field_ui/Plugin/Derivative/FieldUiLocalTask.php

@@ -123,11 +123,13 @@ public function getDerivativeDefinitions(array $base_plugin_definition) {
           'title' => 'Default',
           'route_name' => "field_ui.form_display_overview_$entity_type_id",
           'parent_id' => "field_ui.fields:form_display_overview_$entity_type_id",
+          'weight' => -1,
         );
         $this->derivatives['field_display_default_' . $entity_type_id] = array(
           'title' => 'Default',
           'route_name' => "field_ui.display_overview_$entity_type_id",
           'parent_id' => "field_ui.fields:display_overview_$entity_type_id",
+          'weight' => -1,
         );
 
         // One local task for each form mode.

core/modules/field_ui/lib/Drupal/field_ui/Tests/FieldUIRouteTest.php

@@ -79,6 +79,7 @@ public function testFieldUIRoutes() {
     $this->drupalGet('admin/config/people/accounts/form-display/register');
     $this->assertTitle('Manage form display | Drupal');
     $this->assertLocalTasks();
+    $this->assert(count($this->xpath('//ul/li[1]/a[contains(text(), :text)]', array(':text' => 'Default'))) == 1, 'Default secondary tab is in first position.');
   }
 
   /**