diff --git a/core/modules/system/src/Plugin/Condition/CurrentThemeCondition.php b/core/modules/system/src/Plugin/Condition/CurrentThemeCondition.php
index d282963aa6..65feda583a 100644
--- a/core/modules/system/src/Plugin/Condition/CurrentThemeCondition.php
+++ b/core/modules/system/src/Plugin/Condition/CurrentThemeCondition.php
@@ -84,6 +84,7 @@ public function buildConfigurationForm(array $form, FormStateInterface $form_sta
       '#options' => array_map(function ($theme_info) {
         return $theme_info->info['name'];
       }, $this->themeHandler->listInfo()),
+      '#empty_option' => $this->t('- Any -'),
     ];
     return parent::buildConfigurationForm($form, $form_state);
   }
@@ -111,11 +112,18 @@ public function evaluate() {
    * {@inheritdoc}
    */
   public function summary() {
-    if ($this->isNegated()) {
-      return $this->t('The current theme is not @theme', ['@theme' => $this->configuration['theme']]);
+    $theme = $this->configuration['theme'];
+
+    if ($theme) {
+      $summary = $this->isNegated() ?
+        $this->t('The current theme is not @theme.', ['@theme' => $theme]) : $this->t('The current theme is @theme.', ['@theme' => $theme]);
+    }
+    else {
+      $summary = $this->isNegated() ?
+        $this->t('The current theme is not of any enabled theme.') : $this->t('The current theme is one of enabled theme.');
     }
 
-    return $this->t('The current theme is @theme', ['@theme' => $this->configuration['theme']]);
+    return $summary;
   }
 
   /**
diff --git a/core/tests/Drupal/KernelTests/Core/Plugin/Condition/CurrentThemeConditionTest.php b/core/tests/Drupal/KernelTests/Core/Plugin/Condition/CurrentThemeConditionTest.php
index 7a69d2eb04..e1fe9b6edd 100644
--- a/core/tests/Drupal/KernelTests/Core/Plugin/Condition/CurrentThemeConditionTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Plugin/Condition/CurrentThemeConditionTest.php
@@ -31,8 +31,8 @@ public function testCurrentTheme() {
     $condition_negated = $manager->createInstance('current_theme');
     $condition_negated->setConfiguration(['theme' => 'test_theme', 'negate' => TRUE]);
 
-    $this->assertEqual($condition->summary(), SafeMarkup::format('The current theme is @theme', ['@theme' => 'test_theme']));
-    $this->assertEqual($condition_negated->summary(), SafeMarkup::format('The current theme is not @theme', ['@theme' => 'test_theme']));
+    $this->assertEqual($condition->summary(), SafeMarkup::format('The current theme is @theme.', array('@theme' => 'test_theme')));
+    $this->assertEqual($condition_negated->summary(), SafeMarkup::format('The current theme is not @theme.', array('@theme' => 'test_theme')));
 
     // The expected theme has not been set up yet.
     $this->assertFalse($condition->execute());