Index: user.module
===================================================================
--- user.module	(revision 952)
+++ user.module	(working copy)
@@ -735,8 +735,8 @@
 
     switch ($delta) {
       case 0:
-        // For usability's sake, avoid showing two login forms on one page.
-        if (!$user->uid && !(arg(0) == 'user' && !is_numeric(arg(1)))) {
+        // For usability's sake, avoid showing login form for logged-in users.
+        if (!$user->uid) {
 
           $block['subject'] = t('User login');
           $block['content'] = drupal_get_form('user_login_block');
@@ -807,6 +807,16 @@
 }
 
 /**
+ * Implementation of hook_form_alter().
+ */
+function user_form_block_admin_configure_alter(&$form, &$form_state) {
+  // UI enhancement. See: http://drupal.org/node/893868#comment-3788158
+  if (arg(4) == 'user' && arg(5) == 0) {
+    $form['page_vis_settings']['visibility']['#title'] = t('Show block on specific pages. Please note that for usability reasons this block will not render for logged-in users');
+  }
+}
+
+/**
  * Process variables for user-picture.tpl.php.
  *
  * The $variables array contains the following arguments: