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
General Information
This pertains only to Joomla! version(s):- 3.2.x
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