AJAX and Content History menu items are displaying in the components menu
From Joomla! Documentation
When a site is upgraded from Joomla 3.1 to 3.2 using FTP or another manual upgrade, a number of extensions show up through the discover install method.
Versions affected
What is the cause
When Discovery Install is used for those extensions, AJAX and Content History show up in Components sub-menu.
How to fix
Create a backup, then delete the "com_ajax" entry in the _menu table (you can search for it in the title column). Afterward, delete the "com_contenthistory" entry in the same table.
You can remove that using phpMyAdmin dropping the row in #__menu that refers to com_ajax.
DELETE FROM `#__menu` WHERE component_id = (SELECT extension_id FROM `#__extensions` WHERE `name` = 'com_ajax')
Replace #_ with your prefix