Secure your site!! No-one will be able edit/modify system files(theme+plugins) from Wordpress Dashboard,even admins (So, only from FTP can be edited)... It is useful, when you share Admin access to others. IF PROBLEMS, JUST REMOVE PLUGIN.
(P.S.!! This is a LIGHTWEIGHT (NON-SLOWING) Plugin. See other MUST-HAVE PLUGINS for everyone. )