--- a/logintoboggan.module	2015-05-01 18:53:30.000000000 +0300
+++ b/logintoboggan.module	2018-02-01 19:13:37.000000000 +0200
@@ -1028,28 +1028,33 @@
 
 function logintoboggan_process_login($account, &$edit, $redirect = array()){
   global $user;
+  // restrict logintoboggan module do anything in case user is already logged in.
+  // It breaks panel pages with user login block (admin view).
+  if (!empty($account->uid) || $user->uid == 0) {
+    $user = user_load($account->uid);
+    user_login_finalize($edit);
+    // In the special case where a user is validating but they did not create their
+    // own password, show a user message letting them know to change their password.
+    if (variable_get('user_email_verification', TRUE)) {
+      watchdog('user', 'User %name used one-time login link at time %timestamp.', array(
+        '%name' => $user->name,
+        '%timestamp' => REQUEST_TIME
+      ));
+      drupal_set_message(t('You have just used your one-time login link. It is no longer possible to use this link to login. Please change your password.'));
+    }
 
-  $user = user_load($account->uid);
-  user_login_finalize($edit);
-
-  // In the special case where a user is validating but they did not create their
-  // own password, show a user message letting them know to change their password.
-  if (variable_get('user_email_verification', TRUE)) {
-    watchdog('user', 'User %name used one-time login link at time %timestamp.', array('%name' => $user->name, '%timestamp' => REQUEST_TIME));
-    drupal_set_message(t('You have just used your one-time login link. It is no longer possible to use this link to login. Please change your password.'));
-  }
+    if (isset($redirect[0]) && $redirect[0] != '') {
+      return $redirect;
+    }
 
-  if (isset($redirect[0]) && $redirect[0] != '') {
-    return $redirect;
+    return array(
+      'user/' . $user->uid,
+      array(
+        'query' => array(),
+        'fragment' => '',
+      ),
+    );
   }
-
-  return array(
-    'user/'. $user->uid,
-    array(
-      'query' => array(),
-      'fragment' => '',
-    ),
-  );
 }
 
 function logintoboggan_eml_validate_url($account, $url_options){