diff -up ./user.module ../user.local//user.module
--- ./user.module	2010-08-01 13:48:19.000000000 -0300
+++ ../user.local//user.module	2010-08-01 13:43:22.000000000 -0300
@@ -745,7 +745,7 @@ function user_block($op = 'list', $delta
 
       case 1:
         if ($menu = menu_tree()) {
-          $block['subject'] = $user->uid ? check_plain($user->name) : t('Navigation');
+          $block['subject'] = $user->uid ? theme('username', $user) : t('Navigation');
           $block['content'] = $menu;
         }
         return $block;
diff -up ./user.pages.inc ../user.local//user.pages.inc
--- ./user.pages.inc	2010-08-01 13:48:50.000000000 -0300
+++ ../user.local//user.pages.inc	2010-08-01 13:43:22.000000000 -0300
@@ -164,7 +164,7 @@ function user_logout() {
  * Menu callback; Displays a user or user profile page.
  */
 function user_view($account) {
-  drupal_set_title(check_plain($account->name));
+  drupal_set_title(theme('username', $account));
   // Retrieve all profile fields and attach to $account->content.
   user_build_content($account);
 
@@ -235,7 +235,7 @@ function template_preprocess_user_profil
  * @see user_edit_submit()
  */
 function user_edit($account, $category = 'account') {
-  drupal_set_title(check_plain($account->name));
+  drupal_set_title(theme('username', $account));
   return drupal_get_form('user_profile_form', $account, $category);
 }
 
Only in .: user_theme_username.patch