diff --git a/plugin/tmgmt.ui.translator.inc b/plugin/tmgmt.ui.translator.inc
index 2705ced..ce521c1 100644
--- a/plugin/tmgmt.ui.translator.inc
+++ b/plugin/tmgmt.ui.translator.inc
@@ -37,7 +37,7 @@ class TMGMTDefaultTranslatorUIController extends TMGMTPluginBase implements TMGM
         '#collapsed' => TRUE,
       );
 
-      $options = array(LANGUAGE_NONE => t('Undefined'));
+      $options = array(LANGUAGE_NONE => '(' . t('Undefined') . ')');
       $non_configured = array();
       foreach ($supported_remote_languages as $language) {
         $options[$language] = $language;
diff --git a/tests/tmgmt_test.plugin.translator.inc b/tests/tmgmt_test.plugin.translator.inc
index ab21147..dfb5ac4 100644
--- a/tests/tmgmt_test.plugin.translator.inc
+++ b/tests/tmgmt_test.plugin.translator.inc
@@ -105,4 +105,11 @@ class TMGMTTestTranslatorPluginController extends TMGMTDefaultTranslatorPluginCo
   public function rejectForm($form, &$form_state) {
     return $form;
   }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getSupportedRemoteLanguages(TMGMTTranslator $translator) {
+    return variable_get('tmgmt_test_supported_remote_languages', array());
+  }
 }
diff --git a/ui/tmgmt_ui.test b/ui/tmgmt_ui.test
index 7b6528b..e0c781a 100644
--- a/ui/tmgmt_ui.test
+++ b/ui/tmgmt_ui.test
@@ -628,4 +628,59 @@ class TMGMTUITestCase extends TMGMTBaseTestCase {
     $this->assertNoText($node_sk->title);
   }
 
+  /**
+   * Test the translator language mapping settings form part.
+   */
+  function testLanguageMappingSettingsUi() {
+    $this->loginAsAdmin();
+
+    // The initial state when no supported remote languages are provided.
+    $this->drupalGet('admin/config/regional/tmgmt_translator/manage/test_translator');
+    $this->assertFieldByName('settings[remote_languages_mappings][en]', LANGUAGE_NONE);
+    $this->assertFieldByName('settings[remote_languages_mappings][de]', LANGUAGE_NONE);
+    $this->assertFieldByName('settings[remote_languages_mappings][el]', LANGUAGE_NONE);
+    $this->assertFieldByName('settings[remote_languages_mappings][es]', LANGUAGE_NONE);
+
+    // Set supported remote languages that need to correspond with the result
+    // of getDefaultRemoteLanguagesMappings().
+    variable_set('tmgmt_test_supported_remote_languages', array('en-us', 'de-ch', 'el'));
+    $this->drupalGet('admin/config/regional/tmgmt_translator/manage/test_translator');
+
+    // Test if the values have been preselected correctly in the initial state.
+    $this->assertFieldByName('settings[remote_languages_mappings][en]', 'en-us');
+    $this->assertFieldByName('settings[remote_languages_mappings][de]', 'de-ch');
+    $this->assertFieldByName('settings[remote_languages_mappings][el]', 'el');
+    $this->assertFieldByName('settings[remote_languages_mappings][es]', LANGUAGE_NONE);
+
+    // As "es" language has no target language we should get the warning msg.
+    $this->assertRaw(t('Local language %list does not have target language and thus cannot be used for translation.', array('%list' => 'es')));
+
+    // Save the settings form with having "el" language selected for two local
+    // languages. It must trigger an validation error.
+    $this->drupalPost(NULL, array('settings[remote_languages_mappings][es]' => 'el'), t('Save translator'));
+    $this->assertRaw(t('Remote language %list is assigned to more than one local language.', array('%list' => 'el')));
+
+    // Save the mappings and test if saved correctly.
+    $this->drupalPost(NULL, array('settings[remote_languages_mappings][es]' => LANGUAGE_NONE), t('Save translator'));
+    entity_get_controller('tmgmt_translator')->resetCache();
+    $translator = tmgmt_translator_load('test_translator');
+    $this->assertEqual($translator->getSetting('remote_languages_mappings'), array (
+      'en' => 'en-us',
+      'de' => 'de-ch',
+      'el' => 'el',
+      'es' => 'und',
+    ));
+
+    // Simulate a change of the supported remote language list.
+    variable_set('tmgmt_test_supported_remote_languages', array('en-us', 'de-ch', 'es'));
+    $this->drupalGet('admin/config/regional/tmgmt_translator/manage/test_translator');
+    // The "el" language disappeared and is now not configured. The "es"
+    // language appeared but is still considered as not configured.
+    $this->assertRaw(t('Local languages %list do not have target language and thus cannot be used for translation.', array('%list' => 'el, es')));
+    $this->assertFieldByName('settings[remote_languages_mappings][en]', 'en-us');
+    $this->assertFieldByName('settings[remote_languages_mappings][de]', 'de-ch');
+    $this->assertFieldByName('settings[remote_languages_mappings][el]', LANGUAGE_NONE);
+    $this->assertFieldByName('settings[remote_languages_mappings][es]', LANGUAGE_NONE);
+  }
+
 }