diff -u b/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
--- b/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -525,7 +525,7 @@
       // Localize the theme description.
       $current_theme['description'] = t($theme->info['description']);
 
-      // Style theme info
+      // Style theme info.
       $theme->classes[] = 'theme-selector';
       $theme->classes[] = 'clearfix';
       $current_theme['attributes'] = new Attribute(array('class' => $theme->classes));