[Plugin: Ultimate Security Checker] Turning off file edits has unintended consequences

One of the suggestion from Ultimate Security Checker was

It’s better to turn off the file editor for plugins and themes in WordPress admin.

I googled how to do this and the suggestion was to add the line

define(‘DISALLOW_FILE_MODS’,true);

to wp-config.php.
However, when I did this, the dropdown menu in both the Dashboard tab and the Plugins tab stopped working. This meant I wasn’t able to get to the automatic updates pages for plugins or WordPress.
Does anyone have an alternate method of turning off the file editor that doesn’t have this side effect?

http://wordpress.org/extend/plugins/ultimate-security-checker/