diff --git a/main/admin/dashboard_add_users_to_user.php b/main/admin/dashboard_add_users_to_user.php
index acca6bc53d..713645da51 100755
--- a/main/admin/dashboard_add_users_to_user.php
+++ b/main/admin/dashboard_add_users_to_user.php
@@ -32,7 +32,7 @@ $tbl_user = Database::get_main_table(TABLE_MAIN_USER);
 $tbl_access_url_rel_user = Database::get_main_table(TABLE_MAIN_ACCESS_URL_REL_USER);
 
 // initializing variables
-$user_id = intval($_GET['user']);
+$user_id = isset($_GET['user']) ? (int) $_GET['user'] : 0;
 $user_info = api_get_user_info($user_id);
 $user_anonymous = api_get_anonymous_id();
 $current_user_id = api_get_user_id();
diff --git a/main/auth/courses.php b/main/auth/courses.php
index 9e4926f5d9..20ef35fc5a 100755
--- a/main/auth/courses.php
+++ b/main/auth/courses.php
@@ -199,7 +199,7 @@ switch ($action) {
         exit;
         break;
     case 'createcoursecategory':
-        $courseController->categoryList($action);
+        $courseController->categoryList();
         break;
     case 'deletecoursecategory':
         $courseController->courseList($action);
@@ -213,19 +213,6 @@ switch ($action) {
         }
         header('Location: '.api_get_self());
         exit;
-        /* if (!CoursesAndSessionsCatalog::is(CATALOG_SESSIONS)) {
-            $courseController->courses_categories(
-                $action,
-                $categoryCode,
-                null,
-                null,
-                null,
-                $limit
-            );
-        } else {
-            header('Location: ' . api_get_self());
-            exit;
-        }*/
         break;
     case 'display_random_courses':
         if (!$user_can_view_page) {
diff --git a/main/auth/courses_controller.php b/main/auth/courses_controller.php
index 1e4eea6b48..c892ff21ef 100755
--- a/main/auth/courses_controller.php
+++ b/main/auth/courses_controller.php
@@ -57,20 +57,12 @@ class CoursesController
     }
 
     /**
-     * It's used for listing categories,
-     * render to categories_list view.
+     * It's used for listing categories, render to categories_list view.
      *
-     * @param string $action
-     * @param string $message confirmation message(optional)
-     * @param string $error   error message(optional)
      */
-    public function categoryList($action, $message = '', $error = '')
+    public function categoryList()
     {
         api_block_anonymous_users();
-
-        $data = [];
-        $data['user_course_categories'] = CourseManager::get_user_course_categories(api_get_user_id());
-
         $stok = Security::get_token();
         $actions = Display::url(
             Display::return_icon('back.png', get_lang('Back'), '', '32'),
diff --git a/main/course_home/activity.php b/main/course_home/activity.php
index b52534ccd9..b51be242eb 100755
--- a/main/course_home/activity.php
+++ b/main/course_home/activity.php
@@ -12,7 +12,7 @@
  *
  * @package chamilo.course_home
  */
-$id = isset($_GET['id']) ? intval($_GET['id']) : null;
+$id = isset($_GET['id']) ? (int) $_GET['id'] : null;
 $course_id = api_get_course_int_id();
 $session_id = api_get_session_id();
 
@@ -29,8 +29,6 @@ if (api_is_platform_admin()) {
         /*
         * Process hiding a tools from available tools.
         */
-        //where $id is set?
-        $id = intval($id);
         Database::query("DELETE FROM $tool_table WHERE c_id = $course_id AND id='$id' AND added_tool=1");
     }
 }
@@ -45,9 +43,7 @@ if ($enabled === 'true') {
 }
 
 //	COURSE ADMIN ONLY VIEW
-
 $blocks = [];
-
 // Start of tools for CourseAdmins (teachers/tutors)
 if ($session_id === 0 && api_is_course_admin() && api_is_allowed_to_edit(null, true)) {
     $content .= '<div class="alert alert-success" style="border:0px; margin-top: 0px;padding:0px;">
diff --git a/main/inc/lib/pear/HTML/Common.php b/main/inc/lib/pear/HTML/Common.php
index 822e08a3c8..21cb6f1840 100755
--- a/main/inc/lib/pear/HTML/Common.php
+++ b/main/inc/lib/pear/HTML/Common.php
@@ -241,7 +241,7 @@ class HTML_Common
         if (isset($attributes[$attr])) {
             unset($attributes[$attr]);
         }
-    } //end func _removeAttr
+    }
 
     /**
      * Returns the value of the given attribute
@@ -251,14 +251,15 @@ class HTML_Common
      * @access    public
      * @return    string|null   returns null if an attribute does not exist
      */
-    function getAttribute($attr)
+    public function getAttribute($attr)
     {
         $attr = strtolower($attr);
         if (isset($this->_attributes[$attr])) {
             return $this->_attributes[$attr];
         }
+
         return null;
-    } //end func getAttribute
+    }
 
     /**
      * Sets the value of the attribute