diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index 26a1c3d..ff27183 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -553,6 +553,15 @@ public function processForm($form_id, &$form, &$form_state) {
       if (isset($form['#token']) && $form['#token'] === FALSE) {
         unset($form['#token']);
       }
+      // Form values for programmed form submissions typically do not include a
+      // value for the submit button. But without a triggering element, a
+      // potentially existing #limit_validation_errors property on the primary
+      // submit button is not taken account. Therefore, check whether there is
+      // exactly one submit button in the form, and if so, automatically use it
+      // as triggering_element.
+      if ($form_state['programmed'] && !isset($form_state['triggering_element']) && count($form_state['buttons']) == 1) {
+        $form_state['triggering_element'] = reset($form_state['buttons']);
+      }
       $this->validateForm($form_id, $form, $form_state);
 
       // drupal_html_id() maintains a cache of element IDs it has seen, so it
diff --git a/core/modules/system/lib/Drupal/system/Tests/Form/TriggeringElementProgrammedUnitTest.php b/core/modules/system/lib/Drupal/system/Tests/Form/TriggeringElementProgrammedUnitTest.php
new file mode 100644
index 0000000..72e57ec
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/Form/TriggeringElementProgrammedUnitTest.php
@@ -0,0 +1,97 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Form\TriggeringElementProgrammedUnitTest.
+ */
+
+namespace Drupal\system\Tests\Form;
+
+use Drupal\Component\Utility\String;
+use Drupal\Core\Form\FormInterface;
+use Drupal\simpletest\DrupalUnitTestBase;
+
+/**
+ * Tests detection of triggering_element for programmed form submissions.
+ */
+class TriggeringElementProgrammedUnitTest extends DrupalUnitTestBase implements FormInterface {
+
+  public static $modules = array('system');
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Form triggering element programmed determination',
+      'description' => 'Tests detection of triggering_element for programmed form submissions.',
+      'group' => 'Form API',
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'triggering_element_programmed_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, array &$form_state) {
+    $form['one'] = array(
+      '#type' => 'textfield',
+      '#title' => 'One',
+      '#required' => TRUE,
+    );
+    $form['two'] = array(
+      '#type' => 'textfield',
+      '#title' => 'Two',
+      '#required' => TRUE,
+    );
+    $form['actions'] = array('#type' => 'actions');
+    $form['actions']['submit'] = array(
+      '#type' => 'submit',
+      '#value' => 'Save',
+      '#limit_validation_errors' => array(
+        array($form_state['input']['section']),
+      ),
+      // Required for #limit_validation_errors.
+      '#submit' => array(array($this, 'submitForm')),
+    );
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, array &$form_state) {
+    // Verify that the only submit button was recognized as triggering_element.
+    $this->assertEqual($form['actions']['submit']['#array_parents'], $form_state['triggering_element']['#array_parents']);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, array &$form_state) {
+  }
+
+  /**
+   * Tests that #limit_validation_errors of the only submit button takes effect.
+   */
+  function testLimitValidationErrors() {
+    // Programmatically submit the form.
+    $form_state['values'] = array();
+    $form_state['values']['section'] = 'one';
+    $form_builder = $this->container->get('form_builder');
+    $form_builder->submitForm($this, $form_state);
+
+    // Verify that only the specified section was validated.
+    $errors = $form_builder->getErrors($form_state);
+    $this->assertTrue(isset($errors['one']), "Section 'one' was validated.");
+    $this->assertFalse(isset($errors['two']), "Section 'two' was not validated.");
+
+    // Verify that there are only values for the specified section.
+    $this->assertTrue(isset($form_state['values']['one']), "Values for section 'one' found.");
+    $this->assertFalse(isset($form_state['values']['two']), "Values for section 'two' not found.");
+  }
+
+}