This policy setting allows you to manage whether users have the ability to allow or deny add-ons through Add-On Manager.If you enable this policy setting users cannot enable or disable add-ons through Add-On Manager. The only exception occurs if an add-on has been specifically entered into the 'Add-On List' policy setting in such a way as to allow users to continue to manage the add-on. In this case the user can still manage the add-on through the Add-On Manager.If you disable or do not configure this policy setting the appropriate controls in the Add-On Manager will be available to the user.
Windows Components\Internet Explorer
At least Internet Explorer 6.0 in Windows XP with Service Pack 2 or Windows Server 2003 with Service Pack 1